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C++ Programming Code Examples

C++ > Games Code Examples

Heart Breaking Kid

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/* Heart Breaking Kid */ #include <stdio.h> #include <ctype.h> #include <alloc.h> #include <graphics.h> #include <dos.h> #include <stdlib.h> #include <conio.h> #define n 25 void start(void); void end(void); void rhits(void); void yhits(void); void phits(void); char *msg; void *ball, *ball1, *ball2, *gun, *bomb[n]; void *rhrt[n], *yhrt[n], *phrt[n]; int rflag[n], yflag[n], pflag[n]; int rx[n], ry[n], yx[n], yy[n], px[n], py[n]; int j, life = 3; int rin=0, yin=0, pin=0; unsigned int size,size1,size2,size3,size4; int count = 0, r = 10, bct=0; int nohits = 0, i; int ats = 0; int xend = 400, yend = 450; char che = 3, ch; int flag = 1, x = 5, gx = 4, hitflag[n]; int speed = 1, hity[n], hitx[n]; int x1 = 200, x2 = 377; int ti=500; int flag1 = 1, flag2 = 1; int rhit = 0, yhit = 0, phit = 0; struct time t; void main(void) { int gd = DETECT, gm; initgraph(&gd, &gm, "c:\tc\bgi"); sprintf(msg,"%c",che); setcolor(RED); settextstyle(0,0,30); outtextxy(getmaxx()/2-130,getmaxy()/2-100,msg); setcolor(WHITE); settextstyle(0,0,0); outtextxy(getmaxx()/2-100,getmaxy()/2-50,"Heart Break Kid Game"); getch(); cleardevice(); start(); for(i=0;i<n;i++) { hitflag[i] = 0; rflag[i] = 0; yflag[i] = 0; pflag[i] = 0; } setcolor(RED); settextstyle(0,0,2); outtextxy(8,10,msg); setcolor(12); setlinestyle(0,0,THICK_WIDTH); rectangle(1,1,xend,getmaxy()); rectangle(1,1,getmaxx()-1,getmaxy()-1); setfillstyle(10,12); bar(xend+1,2,getmaxx()-2,100); rectangle(xend,100,getmaxx()-1,200); line(xend,285,getmaxx(),285); line(1,yend,getmaxx(),yend); setcolor(RED); settextstyle(0,0,2); outtextxy(xend+20,200+10,msg); setcolor(YELLOW); settextstyle(0,0,2); outtextxy(xend+110,200+10,msg); setcolor(12); settextstyle(0,0,2); outtextxy(xend+195,200+10,msg); setcolor(RED); setlinestyle(0,0,NORM_WIDTH); circle(r+5,r+5,r); setcolor(YELLOW); settextstyle(0,0,2); outtextxy(203,155,msg); setcolor(YELLOW); setlinestyle(0,0,NORM_WIDTH); circle(r+200,r+150,r); setcolor(12); settextstyle(0,0,2); outtextxy(xend-20,255,msg); setcolor(12); setlinestyle(0,0,NORM_WIDTH); circle(xend-r-3,r+250,r); setcolor(11); setlinestyle(0,0,THICK_WIDTH); line(5,yend-5,20,yend-5); line(5,yend-5,13,yend-14); line(20,yend-5,13,yend-14); size = imagesize(5,5,25,25); ball = malloc(size); getimage(5,5,25,25,ball); size = imagesize(200,150,220,170); ball1 = malloc(size); getimage(200,150,220,170,ball1); size = imagesize(377,250,397,270); ball2 = malloc(size); getimage(377,250,397,270,ball2); size = imagesize(4,yend-4,21,yend-14); gun = malloc(size); getimage(4,yend-4,21,yend-14,gun); setfillstyle(1,12); bar(4,yend+3,xend-3,getmaxy()-4); setcolor(11); settextstyle(0,0,0); setcolor(12); settextstyle(4,0,2); outtextxy(xend+25,20,"HEART BREAK KID"); outtextxy(xend+50,55,"GAME ZONE"); settextstyle(0,0,1); setcolor(12); outtextxy(xend+10,315,"Right Arrow Move Right Side"); outtextxy(xend+10,345,"Left Arrow Move Left Side"); outtextxy(xend+10,375,"Up Arrow To Fire The Arrow"); outtextxy(xend+10,405,"Exit"); randomize(); while(1) { if(life==0) { delay(1000); end(); } gotoxy(52,16); printf("%3d",rhit); gotoxy(63,16); printf("%3d",yhit); gotoxy(74,16); printf("%3d",phit); if(life<0) life = 0; gotoxy(55,12); printf("Speed : %d Lifes : %2d",speed,life); gotoxy(55,10); printf("Total Points : %4d",count); gotoxy(55,8); printf("No Of Attempts : %4d",ats); if(random(200-speed*10)==150-speed*5) rhits(); if(random(200-speed*10)==77-speed*5) phits(); if(random(200-speed*10)==111-speed*5) yhits(); if(kbhit()) { ch = getch(); if(ch==0) { ch = getch(); putimage(gx,yend-14,gun,XOR_PUT); if(ch==75) { if(gx>=15) gx -= 15; } else if(ch==77) { if(gx<=xend-25) gx += 15; } putimage(gx,yend-14,gun,XOR_PUT); if(ch==72&&life>0) { ats += 1; int remflag = 0; for(i=0;i<n;i++) { if(hitflag[i]>1) { hitflag[i]= 1; remflag = 1; hitx[i] = gx + 8 - 3; hity[i] = yend - 14 - 15; putimage(hitx[i],hity[i],bomb[i],XOR_PUT); break; } } if(remflag==0) { for(i=0;i<n;i++) if(hitflag[i]==0) { bct = i; nohits = i; break; } hitflag[bct] = 1; setcolor(10); setlinestyle(0,0,NORM_WIDTH); line(gx+8,yend-15,gx+8,yend-14-15); line(gx+8,yend-14-15,gx+5,yend-14-10); line(gx+8,yend-14-15,gx+11,yend-14-10); size1 = imagesize(gx+8-3,yend-15,gx+8+3,yend-14-15); bomb[bct] = malloc(size1); getimage(gx+8-3,yend-15,gx+8+3,yend-14-15,bomb[bct]); hitx[bct] = gx + 8 - 3; hity[bct] = yend - 14 - 15; } } } if(tolower(ch)=='e') { end(); } } for(i=0;i<n;i++) if(hitflag[i]==1) { putimage(hitx[i],hity[i],bomb[i],XOR_PUT); hity[i] = hity[i] - 8; if(hitx[i]>=x&&hitx[i]<=x+20&&hity[i]>=5&&hity[i]<=25) { rhits(); count += 3; rhit += 1; hitflag[i] = 2; } if(hitx[i]>=x1&&hitx[i]<=x1+20&&hity[i]>=150&&hity[i]<=170) { yhits(); count += 2; yhit+=1; hitflag[i] = 2; } if(hitx[i]>=x2&&hitx[i]<=x2+20&&hity[i]>=250&&hity[i]<=270) { phits(); count += 1; phit+=1; hitflag[i] = 2; } if(hity[i]<=2) { hitflag[i] = 2; } if(hitflag[i]==1) { putimage(hitx[i],hity[i],bomb[i],XOR_PUT); } } if(ti>=500) { gettime(&t); sprintf(msg," Current Time:%2d:%02d:%02d",t.ti_hour, t.ti_min, t.ti_sec); setfillstyle(1,12); bar(xend+3,yend+3,getmaxx()-4,getmaxy()-4); setcolor(BLACK); settextstyle(0,0,0); outtextxy(xend+15,yend+10,msg); ti = 0; } putimage(x,5,ball,XOR_PUT); putimage(x1,150,ball1,XOR_PUT); putimage(x2,250,ball2,XOR_PUT); if(flag==1) x += speed; else x -= speed; if(x>=xend-23) { flag = 0; } if(x<=1) { flag = 1; } if(flag1==1) x1 += 1+speed; else x1 -= 1+speed; if(x1>=xend-23) { flag1 = 0; } if(x1<=1) { flag1 = 1; } if(flag2==1) x2 += 2+speed; else x2 -= 2+speed; if(x2>=xend-23) { flag2 = 0; } if(x2<=1) { flag2 = 1; } putimage(x,5,ball,XOR_PUT); putimage(x1,150,ball1,XOR_PUT); putimage(x2,250,ball2,XOR_PUT); for(i=0;i<n;i++) if(rflag[i]==1) putimage(rx[i],ry[i],rhrt[i],XOR_PUT); for(i=0;i<n;i++) if(yflag[i]==1) putimage(yx[i],yy[i],yhrt[i],XOR_PUT); for(i=0;i<n;i++) if(pflag[i]==1) putimage(px[i],py[i],phrt[i],XOR_PUT); for(i=0;i<n;i++) { if(rflag[i]==1) { ry[i] += speed+2; if(rx[i]>=gx-5&&rx[i]<=gx+20&&ry[i]>=yend-15&&ry[i]<=yend-5) { // count -= 3; rflag[i] = 2; life--; } } } for(i=0;i<n;i++) { if(yflag[i]==1) { yy[i] += speed+1; if(yx[i]>=gx-5&&yx[i]<=gx+20&&yy[i]>=yend-15&&yy[i]<=yend-5) { // count -= 2; yflag[i] = 2; life--; } } } for(i=0;i<n;i++) { if(pflag[i]==1) { py[i] += speed; if(px[i]>=gx-5&&px[i]<=gx+20&&py[i]>=yend-15&&py[i]<=yend-5) { // count -= 1; pflag[i] = 2; life--; } } } for(i=0;i<n;i++) if(ry[i]>=yend-5) { rflag[i] = 2; } for(i=0;i<n;i++) if(yy[i]>=yend-5) { yflag[i] = 2; } for(i=0;i<n;i++) if(py[i]>=yend-5) { pflag[i] = 2; } for(i=0;i<n;i++) if(rflag[i]==1) putimage(rx[i],ry[i],rhrt[i],XOR_PUT); for(i=0;i<n;i++) if(yflag[i]==1) putimage(yx[i],yy[i],yhrt[i],XOR_PUT); for(i=0;i<n;i++) if(pflag[i]==1) putimage(px[i],py[i],phrt[i],XOR_PUT); if(count<5) speed = 1; if(count>=30) speed = 2; if(count>=60) speed = 3; if(count>=90) speed = 4; if(count>=120) speed = 5; delay(12-speed); ti += 12-speed; } } void end(void) { char m[3]; sprintf(m,"%c",3); clrscr(); cleardevice(); restorecrtmode(); textattr(11); cprintf("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ $$$$$$$$$$$$$$"); gotoxy(20,3); cprintf("THE SCORE BOARD FOR HEART BREAK KID"); printf(" "); cprintf("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ $$$$$$$$$$$$$$"); gotoxy(20,7); textattr(11); cprintf("TOTAL NUMBER OF FIRE SHOOTED : %d",ats); gotoxy(20,9); cprintf("TOTAL NUMBER OF POINTS SCORED : %d",count); gotoxy(20,11); textattr(RED); cprintf("TOTAL NUMBER OF HITS TO RED HEART : %d",rhit); gotoxy(20,13); textattr(YELLOW); cprintf("TOTAL NUMBER OF HITS TO YELLOW HEART : %d",yhit); gotoxy(20,15); textattr(12); cprintf("TOTAL NUMBER OF HITS OT PINK HEART : %d",phit); printf(" "); textattr(11); cprintf("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ $$$$$$$$$$$$$$"); getch(); /* int gd=DETECT, gm; initgraph(&gd,&gm,"c:\tc\bgi"); while(!kbhit()) { setcolor(random(getmaxcolor())); settextstyle(0,0,1); outtextxy(random(getmaxx()),random(getmaxy()),m); setcolor(12); settextstyle(0,0,2); outtextxy(100,250,"THANK YOU FOR PLAYING HBK"); } closegraph(); restorecrtmode();*/ exit(0); } void start(void) { cleardevice(); settextstyle(10,0,3); setcolor(12); outtextxy(150,100,"HEART BREAK KID"); settextstyle(0,0,2); getch(); cleardevice(); } void rhits(void) { int rflg = 0; for(j=0;j<n;j++) { if(rflag[j]>1) { rflag[j] = 1; rflg = 1; rx[j] = x-1; ry[j] = 26; putimage(rx[j],ry[j],rhrt[j],XOR_PUT); break; } } if(rflg==0) { rflag[rin] = 1; settextstyle(0,0,1); setcolor(RED); sprintf(msg,"%c",che); outtextxy(x,28,msg); size2 = imagesize(x-1,28-2,x+8,34); rhrt[rin] = malloc(size2); getimage(x-1,28-2,x+8,34,rhrt[rin]); rx[rin] = x-1; ry[rin] = 26; for(j=0;j<n;j++) if(rflag[j]==0) { rin = j; break; } } } void yhits(void) { int yflg = 0; for(j=0;j<n;j++) { if(yflag[j]>1) { yflag[j] = 1; yflg = 1; yx[j] = x1-1; yy[j] = 171; putimage(yx[j],yy[j],yhrt[j],XOR_PUT); break; } } if(yflg==0) { yflag[yin] = 1; settextstyle(0,0,1); setcolor(YELLOW); sprintf(msg,"%c",che); outtextxy(x1,171,msg); size3 = imagesize(x1-1,171,x1+8,179); yhrt[yin] = malloc(size3); getimage(x1-1,171,x1+8,179,yhrt[yin]); yx[yin] = x1-1; yy[yin] = 171; for(j=0;j<n;j++) if(yflag[j]==0) { yin = j; break; } } } void phits(void) { int pflg = 0; for(j=0;j<n;j++) { if(pflag[j]>1) { pflag[j] = 1; pflg = 1; px[j] = x2-1; py[j] = 281; putimage(px[j],py[j],phrt[j],XOR_PUT); break; } } if(pflg==0) { pflag[pin] = 1; settextstyle(0,0,1); setcolor(12); sprintf(msg,"%c",che); outtextxy(x2,281,msg); size4 = imagesize(x2-1,281,x2+8,289); phrt[pin] = malloc(size4); getimage(x2-1,281,x2+8,289,phrt[pin]); px[pin] = x2-1; py[pin] = 281; for(j=0;j<n;j++) if(pflag[j]==0) { pin = j; break; } } }
line() Function in C++
The header file graphics.h contains line() function which is used to draw a line from a point(x1, y1) to point(x2, y2) i.e. (x1, y1) and (x2, y2) are end points of the line. The function line() draws a line on the graphics screen between two specified points. So this function requires four parameters namely x1, y1, x2, and y2 to represent two points. This function draws a line from (x1, y1) coordinates to (x2, y2) coordinates on the graphics screen.
Syntax for line() Function in C++
void line(int x1, int y1, int x2, int y2);
x1
X coordinate of first point
y1
Y coordinate of first point.
x2
X coordinate of second point.
y2
Y coordinate of second point. You can change "linestyle", "pattern", "thickness" of the line by setlinestyle() function.
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/* draw a line in C++ graphic code example */ #include<iostream.h> #include<conio.h> #include<graphics.h> void main() { int gd=DETECT,gm,x,y; clrscr(); initgraph(&gd,&gm,"c:\\TC\\bgi"); //INITIALISING GRAPHICS MODE setlinestyle(0,0,3); outtextxy(300,150,"LINE()"); line(350,60,200,200); outtextxy(300,300," CURRENT POSITION"); linerel(320,350); outtextxy(335,315,"LINEREL()"); outtextxy(30,30," CURRENT POSITION"); lineto(30,200); outtextxy(70,45,"LINETO()"); getch(); closegraph(); }
delay() Function in C++
delay() function is used to hold the program's execution for given number of milliseconds, it is declared in dos.h header file. There can be many instances when we need to create a delay in our programs. C++ provides us with an easy way to do so. We can use a delay() function for this purpose in our code. We can run the code after a specific time in C++ using delay() function.
Syntax for delay() Function in C++
void delay(unsigned int milliseconds);
milliseconds
how many milliseconds to delay The function takes one parameter which is unsigned integer. Here, void suggests that this function returns nothing. 'delay' is the function name.
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/* hold the program's execution for given number of milliseconds by delay() function code example. */ #include<iostream.h> #include<dos.h> //for delay() #include<conio.h> //for getch() int main() { clrscr(); int n; cout<<"Enter the delay (in seconds) you want to make after giving input."<<endl; cin>>n; delay(n*1000); cout<<"This has been printed after "<< n <<" seconds delay"; getch(); return 0; }
getmaxcolor() Function in C++
getmaxcolor() returns highest possible color value. The header file graphics.h contains getmaxcolor() function, which returns maximum color value for current graphics mode and driver. As color numbering starts from zero, total number of colors available for current graphics mode and driver are ( getmaxcolor() + 1 ) .
Syntax for getmaxcolor() Function in C++
#include<graphics.h> int getmaxcolor();
getmaxcolor returns the maximum color value. There are various colors that are also mentioned in graphics.h header file and the possible color values are from 0 - 15: • BLACK – 0 • BLUE – 1 • GREEN – 2 • CYAN – 3 • RED – 4 • MAGENTA – 5 • BROWN – 6 • LIGHTGRAY – 7 • DARKGRAY – 8 • LIGHTBLUE – 9 • LIGHTGREEN – 10 • LIGHTCYAN – 11 • LIGHTRED – 12 • LIGHTMAGENTA – 13 • YELLOW – 14 • WHITE – 15
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/* The getmaxcolor() function returns the largest valid color value for the current video mode. For example, for 4-color CGA mode, this number would be 3. (Color values for this mode range from 0 to 3.) */ /* return maximum color value by getmaxcolor() function code example */ #include <graphics.h> #include <stdio.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; char arr[100]; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // sprintf stands for "String print". // Instead of printing on console, it // store output on char buffer which // are specified in sprintf sprintf(arr, "Maximum number of colors for " "current graphics mode and " "driver = %d", getmaxcolor() + 1); // outtext function displays text // at current position. outtextxy(20, 100, arr); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }
gettime() Function in C++
the gettime() function is used to find current system time. We pass address of a structure varibale of type ( struct time ). gettime() function asks for a time object to be passed and then uses that object to get the current hour and minute etc. The gettime() function fills in the fields of the time structure pointed to by the t parameter. The current system time data is written in DOS format.
Syntax for gettime() Function in C++
#include <dos.h> struct time t; gettime(&t);
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/* find current system time by gettime() function code example. */ #include<stdio.h> #include<dos.h> #include<conio.h> int main() { struct date fecha; struct time hora; union REGS regs; getdate(&fecha); printf("La fecha del sistema es: %d / %d / %d\n",fecha.da_day,fecha.da_mon,fecha.da_year); regs.x.cx = 0x004c; regs.x.dx = 0x4b40; regs.h.ah = 0x86; /* 004c4b40h = 5000000 microsegundos */ int86(0x15,®s,®s); /* Interrupcion 15h suspension de sistema */ gettime(&hora); printf("la hora del sistema es: %d : %d : %d\n",hora.ti_hour,hora.ti_min,hora.ti_sec); getche(); clrscr(); return 0; }
While Loop Statement in C++
In while loop, condition is evaluated first and if it returns true then the statements inside while loop execute, this happens repeatedly until the condition returns false. When condition returns false, the control comes out of loop and jumps to the next statement in the program after while loop. The important point to note when using while loop is that we need to use increment or decrement statement inside while loop so that the loop variable gets changed on each iteration, and at some point condition returns false. This way we can end the execution of while loop otherwise the loop would execute indefinitely. A while loop that never stops is said to be the infinite while loop, when we give the condition in such a way so that it never returns false, then the loops becomes infinite and repeats itself indefinitely.
Syntax for While Loop Statement in C++
while (condition) { // body of the loop }
• A while loop evaluates the condition • If the condition evaluates to true, the code inside the while loop is executed. • The condition is evaluated again. • This process continues until the condition is false. • When the condition evaluates to false, the loop terminates. Do not forget to increase the variable used in the condition, otherwise the loop will never end!
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/* While Loop Statement in C++ language */ // program to find the sum of positive numbers // if the user enters a negative number, the loop ends // the negative number entered is not added to the sum #include <iostream> using namespace std; int main() { int number; int sum = 0; // take input from the user cout << "Enter a number: "; cin >> number; while (number >= 0) { // add all positive numbers sum += number; // take input again if the number is positive cout << "Enter a number: "; cin >> number; } // display the sum cout << "\nThe sum is " << sum << endl; return 0; }
#include Directive in C++
#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.
Syntax for #include Directive in C++
#include "user-defined_file"
Including using " ": When using the double quotes(" "), the preprocessor access the current directory in which the source "header_file" is located. This type is mainly used to access any header files of the user's program or user-defined files.
#include <header_file>
Including using <>: While importing file using angular brackets(<>), the the preprocessor uses a predetermined directory path to access the file. It is mainly used to access system header files located in the standard system directories. Header File or Standard files: This is a file which contains C/C++ function declarations and macro definitions to be shared between several source files. Functions like the printf(), scanf(), cout, cin and various other input-output or other standard functions are contained within different header files. So to utilise those functions, the users need to import a few header files which define the required functions. User-defined files: These files resembles the header files, except for the fact that they are written and defined by the user itself. This saves the user from writing a particular function multiple times. Once a user-defined file is written, it can be imported anywhere in the program using the #include preprocessor. • In #include directive, comments are not recognized. So in case of #include <a//b>, a//b is treated as filename. • In #include directive, backslash is considered as normal text not escape sequence. So in case of #include <a\nb>, a\nb is treated as filename. • You can use only comment after filename otherwise it will give error.
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/* using #include directive in C language */ #include <stdio.h> int main() { /* * C standard library printf function * defined in the stdio.h header file */ printf("I love you Clementine"); printf("I love you so much"); printf("HappyCodings"); return 0; }
closegraph() Function in C++
The header file graphics.h contains closegraph() function which closes the graphics mode, deallocates all memory allocated by graphics system and restores the screen to the mode it was in before you called initgraph. closegraph() function is used to re-enter in the text mode and exit from the graphics mode. If you want to use both text mode and graphics mode in the program then you have to use both initgraph() and closegraph() function in the program. This function deallocates all memory allocated by graphics system and restores the screen to that mode in which it was presented before you called the initgraph() function.
Syntax for closegraph() Function in C++
#include <graphics.h> void closegraph();
This function does not return any value.
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/* closes the graphics mode, deallocates all memory allocated by graphics system and restores the screen to the mode it was in before you called initgraph by closegraph function code example. */ #include <graphics.h> int main() { int gdrive, gmode; char *drvpath = "c:\\bc\\bgi"; detectgraph(&gdrive, &gmode); initgraph(&gdrive, &gmode, drvpath); setbkcolor(0); setcolor(2); cleardevice(); MyOwnFan(320, 230, 0); getch(); closegraph(); return 0; }
kbhit() Function in C++
The kbhit is basically the Keyboard Hit. This function is present at conio.h header file. So for using this, we have to include this header file into our code. The functionality of kbhit() is that, when a key is pressed it returns nonzero value, otherwise returns zero. kbhit() is used to determine if a key has been pressed or not. If a key has been pressed then it returns a non zero value otherwise returns zero.
Syntax for kbhit() Function in C++
#include <conio.h> int kbhit();
Function returns true (non-zero) if there is a character in the input buffer, otherwise false. Note : kbhit() is not a standard library function and should be avoided.
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/* kbhit() function is not defined as part of the ANSI C/C++ standard. It is generally used by Borland's family of compilers. It returns a non-zero integer if a key is in the keyboard buffer. It will not wait for a key to be pressed. */ // C++ program code example to fetch key pressed using kbhit() #include <conio.h> #include <iostream> int main() { char ch; while (1) { if (kbhit) { // Stores the pressed key in ch ch = getch(); // Terminates the loop // when escape is pressed if (int(ch) == 27) break; cout << "Key pressed= " << ch; } } return 0; }
getmaxx() Function in C++
The header file graphics.h contains getmaxx() function which returns the maximum X coordinate for current graphics mode and driver. getmaxx() returns the maximum (screen-relative) x value for the current graphics driver and mode. For example, on a CGA in 320*200 mode, getmaxx returns 319. getmaxx is invaluable for centering, determining the boundaries of a region onscreen, and so on.
Syntax for getmaxx() Function in C++
#include <graphics.h> int getmaxx(void);
getmaxx returns the maximum x screen coordinate. getmaxx() function is used to fetch the maximum X coordinate for the current graphics mode or driver.
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/* Function getmaxx() returns the maximum X coordinate for current graphics mode and driver. */ void loading() { int i,j,x,y; setbkcolor(6); x=getmaxx()/2; y=getmaxy()/2; for(j=30;j<200;j++) { delay(10); setcolor(j/20); arc(x,y,0,180,j-10); } settextstyle(3,0,6); outtextxy(150,250,"!..DOGDE IT..!"); settextstyle(4,0,4); outtextxy(250,340,"LOADING"); for(i=100; i<600; i++) { bar(i,380,i,400); delay(10); } }
setfillstyle() Function in C++
The header file graphics.h contains setfillstyle() function which sets the current fill pattern and fill color. Current fill pattern and fill color is used to fill the area. setfillstyle sets the current fill pattern and fill color. To set a user-defined fill pattern, do not give a pattern of 12 (USER_FILL) to setfillstyle; instead, call setfillpattern.
Syntax for setfillstyle() Function in C++
#include<graphics.h> void setfillstyle(int pattern, int color);
color
Specify the color • BLACK – 0 • BLUE – 1 • GREEN – 2 • CYAN – 3 • RED – 4 • MAGENTA – 5 • BROWN – 6 • LIGHTGRAY – 7 • DARKGRAY – 8 • LIGHTBLUE – 9 • LIGHTGREEN – 10 • LIGHTCYAN – 11 • LIGHTRED – 12 • LIGHTMAGENTA – 13 • YELLOW – 14 • WHITE – 15
pattern
Specify the pattern • EMPTY_FILL – 0 • SOLID_FILL – 1 • LINE_FILL – 2 • LTSLASH_FILL – 3 • SLASH_FILL – 4 • BKSLASH_FILL – 5 • LTBKSLASH_FILL – 6 • HATCH_FILL – 7 • XHATCH_FILL – 8 • INTERLEAVE_FILL – 9 • WIDE_DOT_FILL – 10 • CLOSE_DOT_FILL – 11 • USER_FILL – 12 If invalid input is passed to setfillstyle, graphresult returns -1(grError), and the current fill pattern and fill color remain unchanged. The EMPTY_FILL style is like a solid fill using the current background color (which is set by setbkcolor). This function does not return any value.
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/* The header file graphics.h contains setfillstyle() function which sets the current fill pattern and fill color. floodfill() function is used to fill an enclosed area. Current fill pattern and fill color is used to fill the area. */ #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // initgraph initializes the // graphics system by loading // a graphics driver from disk initgraph(&gd, &gm, " "); // center and radius of circle int x_circle = 250; int y_circle = 250; int radius=100; // setting border color int border_color = WHITE; // set color and pattern setfillstyle(HATCH_FILL,RED); // x and y is a position and // radius is for radius of circle circle(x_circle,y_circle,radius); // fill the color at location // (x, y) with in border color floodfill(x_circle,y_circle,border_color); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system closegraph(); return 0; }
restorecrtmode() Function in C++
restorecrtmode restores the original video mode detected by initgraph. This function can be used in conjunction with setgraphmode to switch back and forth between text and graphics modes. Textmode should not be used for this purpose; use it only when the screen is in text mode, to change to a different text mode. restorecrtmode is implemented in winbgim, but it does not do any work. This is because both the graphics window and the text window are always open during any Windows program, so there is no need to switch back and forth between the two modes.
Syntax for restorecrtmode() Function in C++
#include <graphics.h> void restorecrtmode(void);
restorecrtmode() restores the original screen mode that existed prior to calling initgraph(). Most often, this represents the text mode. restorecrtmode() and setgraphmode() can be alternately called to switch between text and graphics mode. Function returns nothing.
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/* restore the original screen mode that existed prior to calling initgraph() by restorecrtmode() function code example. */ #include <graphics.h> #include <stdlib.h> #include <stdio.h> #include <conio.h> int main(void) { /* request autodetection */ int gdriver = DETECT, gmode, errorcode; int x, y; /* initialize graphics and local variables */ initgraph(&gdriver, &gmode, ""); /* read result of initialization */ errorcode = graphresult(); if (errorcode != grOk) { /* an error occurred */ printf("Graphics error: %s\n", grapherrormsg(errorcode)); printf("Press any key to halt:"); getch(); exit(1); /* terminate with an error code */ } x = getmaxx() / 2; y = getmaxy() / 2; /* output a message */ settextjustify(CENTER_TEXT, CENTER_TEXT); outtextxy(x, y, "Press any key to exit graphics:"); getch(); /* restore system to text mode */ restorecrtmode(); printf("We're now in text mode.\n"); printf("Press any key to return to graphics mode:"); getch(); /* return to graphics mode */ setgraphmode(getgraphmode()); /* output a message */ settextjustify(CENTER_TEXT, CENTER_TEXT); outtextxy(x, y, "We're back in graphics mode."); outtextxy(x, y+textheight("W"), "Press any key to halt:"); /* clean up */ getch(); closegraph(); return 0; }
setlinestyle() Function in C++
setlinestyle() is a function which is used to draw the line of different- different styles. Turbo C compiler provides five line styles that are solid, dotted, center, dashed and user defined. These all five line styles are already enumerated in graphics.h header file as given below: setlinestyle() function contains three parameters type, pattern and thickness. First parameter contains the type of line like solid, dashed or dotted etc. Second parameter is applicable only when type of line is user defined. Third parameter specifies the thickness of the line it takes values 1 (line thickness of one pixel (normal)) or 3 (line thickness of three pixels (thick).
Syntax for setlinestyle() Function in C++
#include <graphics.h> void setlinestyle(int linestyle, unsigned upattern, int thickness);
linestyle
First parameter contains the type of line like solid, dashed or dotted etc. The enumeration line_styles, which is defined in graphics.h, gives names to these operators: • SOLID_LINE 0 Solid line • DOTTED_LINE 1 Dotted line • CENTER_LINE 2 Centered line • DASHED_LINE 3 Dashed line • USERBIT_LINE 4 User-defined line style
upattern
Second parameter is applicable only when type of line is user defined.
thickness
Third parameter specifies the thickness of the line it takes values 1 (line thickness of one pixel (normal)) or 3 (line thickness of three pixels (thick). • NORM_WIDTH 1 1 pixel wide • THICK_WIDTH 3 3 pixels wide Note: The linestyle parameter does not affect arcs, circles, ellipses, or pie slices. Only the thickness parameter is used. If invalid input is passed to setlinestyle, graphresult returns -11, and the current line style remains unchanged.
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/* setlinestyle() function sets the style for all lines drawn by line, lineto, rectangle, drawpoly, and so on. */ // C Implementation for setlinestyle() #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // variable to change the // line styles int c; // initial coordinate to // draw line int x = 200, y = 100; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // To keep track of lines for ( c = 0 ; c < 5 ; c++ ) { // setlinestyle function setlinestyle(c, 0, 1); // Drawing line line(x, y, x+200, y); y = y + 25; } getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }
bar() Function in C++
bar() function is a C graphics function that is used to draw graphics in the C programming language. The graphics.h header contains functions that work for drawing graphics. The bar() function is also defined in the header file. Bar function is used to draw a 2-dimensional, rectangular filled in bar. Coordinates of left top and right bottom corner are required to draw the bar. Left specifies the X-coordinate of top left corner, top specifies the Y-coordinate of top left corner, right specifies the X-coordinate of right bottom corner, bottom specifies the Y-coordinate of right bottom corner. Current fill pattern and fill color is used to fill the bar. To change fill pattern and fill color use setfillstyle.
Syntax for bar() Function in C++
#include <graphics.h> void bar(int left, int top, int right, int bottom);
left
X coordinate of top left corner.
top
Y coordinate of top left corner.
right
X coordinate of bottom right corner.
bottom
Y coordinate of bottom right corner. Current fill pattern and fill color is used to fill the bar. To change fill pattern and fill color use setfillstyle. This function does not return any value.
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/* The bar() function is used to draw a bar ( of bar graph) which is a 2-dimensional figure. It is filled rectangular figure. The function takes four arguments that are the coordinates of (X, Y) coordinates of the top-left corner of the bar {left and top } and (X, Y) coordinates of the bottom-right corner of the bar {right and bottom}. */ /* draw a filled-in, rectangular, two-dimensional bar by bar() function code example. */ #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // location of sides int left, top, right, bottom; // left, top, right, bottom denotes // location of rectangular bar bar(left = 150, top = 150, right = 190, bottom = 350); bar(left = 220, top = 250, right = 260, bottom = 350); bar(left = 290, top = 200, right = 330, bottom = 350); // y axis line line(100, 50, 100, 350); // x axis line line(100, 350, 400, 350); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }
putimage() Function in C++
putimage puts the bit image previously saved with getimage back onto the screen, with the upper left corner of the image placed at (left,top). bitmap points to the area in memory where the source image is stored. The op parameter to putimage specifies a combination operator that controls how the color for each destination pixel onscreen is computed, based on the pixel already onscreen and the corresponding source pixel in memory.
Syntax for putimage() Function in C++
#include <graphics.h> void putimage(int left, int top, void *bitmap, int op);
left
X coordinate of top left corner of the specified rectangular area
top
Y coordinate of top left corner of the specified rectangular area
bitmap
pointer to the bitmap image in memory
op
operator for putimage. The enumeration putimage_ops, as defined in graphics.h, gives names to these operators. • COPY_PUT 0 Copy • XOR_PUT 1 Exclusive or • OR_PUT 2 Inclusive or • AND_PUT 3 And • NOT_PUT 4 Copy the inverse of the source In other words, COPY_PUT copies the source bitmap image onto the screen, XOR_PUT XORs the source image with the image already onscreen, OR_PUT ORs the source image with that onscreen, and so on. This function does not return any value.
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/* In C++, the putimage() function is used to put the bit image that is saved with getimage() function back to screen. */ /* put the bit image to screen by putimage() function code example */ #include<graphics.h> #include<conio.h> #include<stdlib.h> main() { int gd = DETECT, gm, area, temp1, temp2, left = 25, top = 75; void *p; initgraph(&gd,&gm,"C:\\TC\\BGI"); setcolor(YELLOW); circle(50,100,25); setfillstyle(SOLID_FILL,YELLOW); floodfill(50,100,YELLOW); setcolor(BLACK); setfillstyle(SOLID_FILL,BLACK); fillellipse(44,85,2,6); fillellipse(56,85,2,6); ellipse(50,100,205,335,20,9); ellipse(50,100,205,335,20,10); ellipse(50,100,205,335,20,11); area = imagesize(left, top, left + 50, top + 50); p = malloc(area); setcolor(WHITE); settextstyle(SANS_SERIF_FONT,HORIZ_DIR,2); outtextxy(155,451,"Smiling Face Animation"); setcolor(BLUE); rectangle(0,0,639,449); while(!kbhit()) { temp1 = 1 + random ( 588 ); temp2 = 1 + random ( 380 ); getimage(left, top, left + 50, top + 50, p); putimage(left, top, p, XOR_PUT); putimage(temp1 , temp2, p, XOR_PUT); delay(100); left = temp1; top = temp2; } getch(); closegraph(); return 0; }
#define Directive in C++
In the C++ Programming Language, the #define directive allows the definition of macros within your source code. These macro definitions allow constant values to be declared for use throughout your code. Macro definitions are not variables and cannot be changed by your program code like variables. You generally use this syntax when creating constants that represent numbers, strings or expressions. The syntax for creating a constant using #define in the C++ is: #define token value
Syntax for #define Directive in C++
#define macro-name replacement-text
• Using #define to create Macros Macros also follow the same structure as Symbolic Constants; however, Macros allow arguments to be included in the identifier:
#define SQUARE_AREA(l) ((l) * (l))
Unlike in functions, the argument here is enclosed in parenthesis in the identifier and does not have a type associated with it. Before compilation, the compiler will replace every instance of SQUARE_AREA(l) by ((l) * (l)), where l can be any expression. • Conditional Compilation There are several directives, which can be used to compile selective portions of your program's source code. This process is called conditional compilation. The conditional preprocessor construct is much like the 'if' selection structure. Consider the following preprocessor code:
#ifndef NULL #define NULL 0 #endif
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/* #define directive in C++ language */ #include <bits/stdc++.h> using namespace std; void func1(); void func2(); #pragma startup func1 #pragma exit func2 void func1() { cout << "Inside func1()\n"; } void func2() { cout << "Inside func2()\n"; } int main() { void func1(); void func2(); cout << "Inside main()\n"; return 0; }
Break Statement in C++
Break statement in C++ is a loop control statement defined using the break keyword. It is used to stop the current execution and proceed with the next one. When a compiler calls the break statement, it immediately stops the execution of the loop and transfers the control outside the loop and executes the other statements. In the case of a nested loop, break the statement stops the execution of the inner loop and proceeds with the outer loop. The statement itself says it breaks the loop. When the break statement is called in the program, it immediately terminates the loop and transfers the flow control to the statement mentioned outside the loop.
Syntax for Break Statement in C++
// jump-statement; break;
The break statement is used in the following scenario: • When a user is not sure about the number of iterations in the program. • When a user wants to stop the program based on some condition. The break statement terminates the loop where it is defined and execute the other. If the condition is mentioned in the program, based on the condition, it executes the loop. If the condition is true, it executes the conditional statement, and if the break statement is mentioned, it will immediately break the program. otherwise, the loop will iterate until the given condition fails. if the condition is false, it stops the program.
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/* break statement with while loop code example */ // program to find the sum of positive numbers // if the user enters a negative numbers, break ends the loop // the negative number entered is not added to sum #include <iostream> using namespace std; int main() { int number; int sum = 0; while (true) { // take input from the user cout << "Enter a number: "; cin >> number; // break condition if (number < 0) { break; } // add all positive numbers sum += number; } // display the sum cout << "The sum is " << sum << endl; return 0; }
tolower() Function in C++
Convert uppercase letter to lowercase. Converts c to its lowercase equivalent if c is an uppercase letter and has a lowercase equivalent. If no such conversion is possible, the value returned is c unchanged. The tolower() function in C++ converts a given character to lowercase. It is defined in the cctype header file. Notice that what is considered a letter may depend on the locale being used; In the default "C" locale, an uppercase letter is any of: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z, which translate respectively to: a b c d e f g h i j k l m n o p q r s t u v w x y z.
Syntax for tolower() Function in C++
#include <cctype> int tolower ( int c );
c
Character to be converted, casted to an int, or EOF. The tolower() function accepts the following parameter: c - a character, casted to int type or EOF. The tolower() function returns: Function returns the lowercase equivalent to c, if such value exists, or c (unchanged) otherwise. The value is returned as an int value that can be implicitly casted to char. tolower() function returns: For Alphabets - the ASCII code of the lowercase version of c. For Non-Alphabets - the ASCII code of c. In other locales, if an uppercase character has more than one correspondent lowercase character, this function always returns the same character for the same value of c. In C++, a locale-specific template version of this function (tolower) exists in header <locale>.
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/* convert uppercase letter to lowercase by tolower() function code example */ #include <cctype> #include <iostream> #include <cstring> using namespace std; int main() { char str[] = "Clementine is from USA."; char ch; cout << "The lowercase version of \"" << str << "\" is " << endl; for (int i = 0; i < strlen(str); i++) { // convert str[i] to lowercase ch = tolower(str[i]); cout << ch; } return 0; }
If Else Statement in C++
In computer programming, we use the if statement to run a block code only when a certain condition is met. An if statement can be followed by an optional else statement, which executes when the boolean expression is false. There are three forms of if...else statements in C++: • if statement, • if...else statement, • if...else if...else statement,
Syntax for If Statement in C++
if (condition) { // body of if statement }
The if statement evaluates the condition inside the parentheses ( ). If the condition evaluates to true, the code inside the body of if is executed. If the condition evaluates to false, the code inside the body of if is skipped.
Syntax for If...Else Statement
if (condition) { // block of code if condition is true } else { // block of code if condition is false }
The if..else statement evaluates the condition inside the parenthesis. If the condition evaluates true, the code inside the body of if is executed, the code inside the body of else is skipped from execution. If the condition evaluates false, the code inside the body of else is executed, the code inside the body of if is skipped from execution. The if...else statement is used to execute a block of code among two alternatives. However, if we need to make a choice between more than two alternatives, we use the if...else if...else statement.
Syntax for If...Else...Else If Statement in C++
if (condition1) { // code block 1 } else if (condition2){ // code block 2 } else { // code block 3 }
• If condition1 evaluates to true, the code block 1 is executed. • If condition1 evaluates to false, then condition2 is evaluated. • If condition2 is true, the code block 2 is executed. • If condition2 is false, the code block 3 is executed. There can be more than one else if statement but only one if and else statements. In C/C++ if-else-if ladder helps user decide from among multiple options. The C/C++ if statements are executed from the top down. As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the C else-if ladder is bypassed. If none of the conditions is true, then the final else statement will be executed.
Syntax for If Else If Ladder in C++
if (condition) statement 1; else if (condition) statement 2; . . else statement;
Working of the if-else-if ladder: 1. Control falls into the if block. 2. The flow jumps to Condition 1. 3. Condition is tested. If Condition yields true, goto Step 4. If Condition yields false, goto Step 5. 4. The present block is executed. Goto Step 7. 5. The flow jumps to Condition 2. If Condition yields true, goto step 4. If Condition yields false, goto Step 6. 6. The flow jumps to Condition 3. If Condition yields true, goto step 4. If Condition yields false, execute else block. Goto Step 7. 7. Exits the if-else-if ladder. • The if else ladder statement in C++ programming language is used to check set of conditions in sequence. • This is useful when we want to selectively executes one code block(out of many) based on certain conditions. • It allows us to check for multiple condition expressions and execute different code blocks for more than two conditions. • A condition expression is tested only when all previous if conditions in if-else ladder is false. • If any of the conditional expression evaluates to true, then it will execute the corresponding code block and exits whole if-else ladder.
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/* If Else Statement in C++ Language */ #include <iostream> using namespace std; int main () { // local variable declaration: int a = 100; // check the boolean condition if( a < 20 ) { // if condition is true then print the following cout << "a is less than 20;" << endl; } else { // if condition is false then print the following cout << "a is not less than 20;" << endl; } cout << "value of a is : " << a << endl; return 0; }
gotoxy() Function in C++
Positions cursor in text window. The gotoxy() function places the cursor at the desired location on the screen. This means it is possible to change the cursor location on the screen using the gotoxy() function. It is basically used to print text wherever the cursor is moved. If the coordinates are in any way invalid the call to gotoxy is ignored. Neither argument to gotoxy can be zero.
Syntax for gotoxy() Function in C++
void gotoxy(int x, int y);
x
X coordinate of the position where we want to place the cursor.
y
Y coordinate of the position where we want to place the cursor. This function does not return any value. Do not use this function for Win32s or Win32 GUI applications.
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/* The gotoxy() function places the cursor at the desired location on the screen. This means it is possible to change the cursor location on the screen using the gotoxy() function. It is basically used to print text wherever the cursor is moved. */ // Description: prints grid at given origin (xPos, yPos) // Arguments: // xPos - x coordinate of origin // yPos - y coordinate of origin void Grid::print(int xPos, int yPos){ #ifdef EN_PRINT for(int i = 0;i < GRID_LENGTH;i++){ for(int j = 0;j < GRID_LENGTH;j++){ int x = xPos + 6 * j; int y = yPos + 2 * i; gotoXY(x,y); std::cout<<" "; gotoXY(x,y); std::cout<<m_data[i*GRID_LENGTH + j]; } } #endif }
Structures in C++ Language
In C++, classes and structs are blueprints that are used to create the instance of a class. Structs are used for lightweight objects such as Rectangle, color, Point, etc. Unlike class, structs in C++ are value type than reference type. It is useful if you have data that is not intended to be modified after creation of struct. C++ Structure is a collection of different data types. It is similar to the class that holds different types of data.
Syntax for Structures in C++
struct structureName{ member1; member2; member3; . . . memberN; };
A structure is declared by preceding the struct keyword followed by the identifier(structure name). Inside the curly braces, we can declare the member variables of different types. Consider the following situation:
struct Teacher { char name[20]; int id; int age; }
In the above case, Teacher is a structure contains three variables name, id, and age. When the structure is declared, no memory is allocated. When the variable of a structure is created, then the memory is allocated. Let's understand this scenario. Structures in C++ can contain two types of members: • Data Member: These members are normal C++ variables. We can create a structure with variables of different data types in C++. • Member Functions: These members are normal C++ functions. Along with variables, we can also include functions inside a structure declaration. Structure variable can be defined as: Teacher s; Here, s is a structure variable of type Teacher. When the structure variable is created, the memory will be allocated. Teacher structure contains one char variable and two integer variable. Therefore, the memory for one char variable is 1 byte and two ints will be 2*4 = 8. The total memory occupied by the s variable is 9 byte. The variable of the structure can be accessed by simply using the instance of the structure followed by the dot (.) operator and then the field of the structure.
s.id = 4;
We are accessing the id field of the structure Teacher by using the dot(.) operator and assigns the value 4 to the id field. In C++, the struct keyword is optional before in declaration of a variable. In C, it is mandatory.
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/* Structure is a collection of variables of different data types under a single name. It is similar to a class in that, both holds a collecion of data of different data types. */ #include <iostream> using namespace std; struct Person { char name[50]; int age; float salary; }; int main() { Person p1; cout << "Enter Full name: "; cin.get(p1.name, 50); cout << "Enter age: "; cin >> p1.age; cout << "Enter salary: "; cin >> p1.salary; cout << "\nDisplaying Information." << endl; cout << "Name: " << p1.name << endl; cout <<"Age: " << p1.age << endl; cout << "Salary: " << p1.salary; return 0; }
main() Function in C++
A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.
Syntax for main() Function in C++
void main() { ............ ............ }
void
void is a keyword in C++ language, void means nothing, whenever we use void as a function return type then that function nothing return. here main() function no return any value.
main
main is a name of function which is predefined function in C++ library. In place of void we can also use int return type of main() function, at that time main() return integer type value. 1) It cannot be used anywhere in the program a) in particular, it cannot be called recursively b) its address cannot be taken 2) It cannot be predefined and cannot be overloaded: effectively, the name main in the global namespace is reserved for functions (although it can be used to name classes, namespaces, enumerations, and any entity in a non-global namespace, except that a function called "main" cannot be declared with C language linkage in any namespace). 3) It cannot be defined as deleted or (since C++11) declared with C language linkage, constexpr (since C++11), consteval (since C++20), inline, or static. 4) The body of the main function does not need to contain the return statement: if control reaches the end of main without encountering a return statement, the effect is that of executing return 0;. 5) Execution of the return (or the implicit return upon reaching the end of main) is equivalent to first leaving the function normally (which destroys the objects with automatic storage duration) and then calling std::exit with the same argument as the argument of the return. (std::exit then destroys static objects and terminates the program). 6) (since C++14) The return type of the main function cannot be deduced (auto main() {... is not allowed). 7) (since C++20) The main function cannot be a coroutine.
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/* simple code example by main() function in C++ */ #include <iostream> using namespace std; int main() { int day = 4; switch (day) { case 1: cout << "Monday"; break; case 2: cout << "Tuesday"; break; case 3: cout << "Wednesday"; break; case 4: cout << "Thursday"; break; case 5: cout << "Friday"; break; case 6: cout << "Saturday"; break; case 7: cout << "Sunday"; break; } return 0; }
initgraph() Function in C++
To create a program in Graphics Mode, the first step would be to include the header file graphics.h. This file is required for Graphics programming. After this, the graphics have to be initialized. C Language supports 16 Bit's MS-DOS environment. Initializing the Graphics mode is to call various functions, one such is called initgraph. initgraph initializes the graphics system by loading a graphics driver from disk (or validating a registered driver), and putting the system into graphics mode. To start the graphics system, first call the initgraph function. initgraph loads the graphics driver and puts the system into graphics mode. You can tell initgraph to use a particular graphics driver and mode, or to autodetect the attached video adapter at run time and pick the corresponding driver. If you tell initgraph to autodetect, it calls detectgraph to select a graphics driver and mode. initgraph also resets all graphics settings to their defaults (current position, palette, color, viewport, and so on) and resets graphresult to 0.
Syntax for initgraph() Function in C++
void initgraph (int *graphdriver, int *graphmode, char *pathtodriver);
graphdriver
This is an integer that indicates that the graphics driver has been used.
graphmode
It is also an integer value that detects the available graphics driver and initializes the graphics mode according to its highest resolution.
pathtodriver
This is the path of the directory that first searches the initgraph function graphics driver. If the graphics driver is not available then the system searches it in the current directory. It is necessary to pass the correct value of the three parameters in the initgraph function or else an unpredictable output is obtained.
intgd = DETECT, gm; initgraph (&gd, &gm, " ");
To initialize Graphics mode, you only have to write two lines. Here, we have taken two integer variables 'd' and 'm'. Here, DETECT is an enumeration type that identifies and identifies the proper graphics driver. The initgraph function has to pass the address of both the variables. You can see in the example that we have given a space at the position of the third variable. This means that if you do not know the driver's path then you can leave it blank. The compiler will auto-detect the path. initgraph always sets the internal error code; on success, it sets the code to 0. If an error occurred, *graphdriver is set to -2, -3, -4, or -5, and graphresult returns the same value as listed below: • grNotDetected -2 Cannot detect a graphics card • grFileNotFound -3 Cannot find driver file • grInvalidDriver -4 Invalid driver • grNoLoadMem -5 Insufficient memory to load driver
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/* initgraph initializes the graphics system by loading a graphics driver from disk (or validating a registered driver), and putting the system into graphics mode. To start the graphics system, first call the initgraph function. initgraph loads the graphics driver and puts the system into graphics mode. You can tell initgraph to use a particular graphics driver and mode, or to autodetect the attached video adapter at run time and pick the corresponding driver. */ int DGraphics::Init( int gmode ) { int gdriver = VGA, errorcode; gdriver=installuserdriver("SVGA256",NULL); initgraph(&gdriver, &gmode, ""); if ( (errorcode = graphresult()) != grOk ) { cout << "Error: Graphics - %s\n" << grapherrormsg(errorcode); return FALSE; } ActiveMode=gmode; return TRUE; }
getmaxy() Function in C++
The header file graphics.h contains getmaxy() function which returns the maximum Y coordinate for current graphics mode and driver. getmaxy returns the maximum (screen-relative) y value for the current graphics driver and mode. For example, on a CGA in 320*200 mode, getmaxy returns 199. getmaxy is invaluable for centering, determining the boundaries of a region onscreen, and so on.
Syntax for getmaxy() Function in C++
#include <graphics.h> int getmaxy(void);
getmaxy() returns the maximum y screen coordinate. getmaxy() function is used to fetch the maximum Y coordinate for the current graphics mode or driver.
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/* Function getmaxy() returns the maximum Y coordinate for current graphics mode and driver. */ int main() { int x,y,i; int g=DETECT,d; initgraph(&g,&d,"\tc\bgi"); cleardevice(); x=getmaxx()/2; y=getmaxy()/2; settextstyle(TRIPLEX_FONT, HORIZ_DIR, 3); setbkcolor(rand()); setcolor(4); outtextxy(30,100,"Press"); outtextxy(30,130,"any"); outtextxy(30,160,"key"); outtextxy(30,190, "to"); outtextxy(30,220,"Quit"); while (!kbhit()) { setcolor(rand()); for (int i=0;i<50;i++) circle(x,y,i ); setcolor(rand()); for (int j=70;j<120;j++) circle(x,y,j); setcolor(rand()); for (int k=140;k<190;k++) circle(x,y,k); setcolor(rand()); for (int l=210;l<230;l++) circle(x,y,l); delay(200); } getch(); closegraph(); }
clrscr() Function in C++
It is a predefined function in "conio.h" (console input output header file) used to clear the console screen. It is a predefined function, by using this function we can clear the data from console (Monitor). Using of clrscr() is always optional but it should be place after variable or function declaration only. It is often used at the beginning of the program (mostly after variable declaration but not necessarily) so that the console is clear for our output.
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/* clrscr() function is also a non-standard function defined in "conio.h" header. This function is used to clear the console screen. It is often used at the beginning of the program (mostly after variable declaration but not necessarily) so that the console is clear for our output.*/ #include<iostream.h> #include<conio.h> void main() { int a=10, b=20; int sum=0; clrscr(); // use clrscr() after variable declaration sum=a+b; cout<<"Sum: "<<sum; //clear the console screen clrscr(); getch(); }
getch() Function in C++
The getch() is a predefined non-standard function that is defined in conio.h header file. It is mostly used by the Dev C/C++, MS- DOS's compilers like Turbo C to hold the screen until the user passes a single value to exit from the console screen. It can also be used to read a single byte character or string from the keyboard and then print. It does not hold any parameters. It has no buffer area to store the input character in a program.
Syntax for getch() Function in C++
#include <conio.h> int getch(void);
The getch() function does not accept any parameter from the user. It returns the ASCII value of the key pressed by the user as an input. We use a getch() function in a C/ C++ program to hold the output screen for some time until the user passes a key from the keyboard to exit the console screen. Using getch() function, we can hide the input character provided by the users in the ATM PIN, password, etc. • getch() method pauses the Output Console until a key is pressed. • It does not use any buffer to store the input character. • The entered character is immediately returned without waiting for the enter key. • The entered character does not show up on the console. • The getch() method can be used to accept hidden inputs like password, ATM pin numbers, etc.
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/* wait for any character input from keyboard by getch() function code example. The getch() function is very useful if you want to read a character input from the keyboard. */ // C code to illustrate working of // getch() to accept hidden inputs #include<iostream.h> #include<conio.h> void main() { int a=10, b=20; int sum=0; clrscr(); sum=a+b; cout<<"Sum: "<<sum; getch(); // use getch() befor end of main() }
rectangle() Function in C++
rectangle() is used to draw a rectangle. Coordinates of left top and right bottom corner are required to draw the rectangle. left specifies the X-coordinate of top left corner, top specifies the Y-coordinate of top left corner, right specifies the X-coordinate of right bottom corner, bottom specifies the Y-coordinate of right bottom corner.
Syntax for rectangle() Function in C++
rectangle(int left, int top, int right, int bottom);
left
X coordinate of top left corner.
top
Y coordinate of top left corner.
right
X coordinate of bottom right corner.
bottom
Y coordinate of bottom right corner. To create a rectangle, you have to pass the four parameters in this function. The two parameters represent the left and top upper left corner. Similarly, the right bottom parameter represents the lower right corner of the rectangle. This function does not return any value.
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/* function rectangle() draws a rectangle in graphic mode. */ int main() { // location of left, top, right, bottom int left = 150, top = 150; int right = 450, bottom = 450; // initgraph initializes the graphics system // by loading a graphics driver from disk initgraph(&gd, &gm, ""); // rectangle function rectangle(left, top, right, bottom); left = 200, = 250; right = 150, = 300; rectangle(left, top, right, bottom); left = 100, = 200; right = 450, = 100; rectangle(left, top, right, bottom); getch(); return 0; }
getimage() Function in C++
getimage() function copy a specific portion into memory. This specific image would be any bit image like rectangle, circle or anything else. getimage() copies an image from the screen to memory. Left, top, right, and bottom define the screen area to which the rectangle is copied. Bitmap points to the area in memory where the bit image is stored. The first two words of this area are used for the width and height of the rectangle; the remainder holds the image itself.
Syntax for getimage() Function in C++
#include <graphics.h> void getimage(int left, int top, int right, int bottom, void *bitmap);
left
X coordinate of top left corner
top
Y coordinate of top left corner
right
X coordinate of bottom right corner
bottom
Y coordinate of bottom right corner
bitmap
points to the area in memory where the bit image is stored getimage() function saves a bit image of specified region into memory, region can be any rectangle. This function does not return any value.
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/* getimage() function code example copies an image from the screen to memory. */ /* save a bit image of the specified region displayed on the screen into memory by getimage() function code example. */ #include<stdio.h> #include<conio.h> #include<graphics.h> void main() { int gd=DETECT, gm,size; char *buff; initgraph(&gd,&gm," "); outtextxy(100,80,"Original image:"); rectangle(100,200,200,275); size=http://www.web.com/imagesize(100,200,200,275); buf=malloc(size); getimage(100,200,200,275,buf); outtextxy(100,320,"Captured image:"); putimage(100,340,buf,COPY_PUT); getch(); closegraph(); }
setcolor() Function in C++
setcolor() function is used to set the foreground color in graphics mode. After resetting the foreground color you will get the text or any other shape which you want to draw in that color. setcolor sets the current drawing color to color, which can range from 0 to getmaxcolor. The current drawing color is the value to which pixels are set when lines, and so on are drawn. The drawing colors shown below are available for the CGA and EGA, respectively.
Syntax for setcolor() Function in C++
void setcolor(int color);
color
specify the color setcolor() functions contains only one argument that is color. It may be the color name enumerated in graphics.h header file or number assigned with that color. This function does not return any value. INT VALUES corresponding to Colors: • BLACK 0 • BLUE 1 • GREEN 2 • CYAN 3 • RED 4 • MAGENTA 5 • BROWN 6 • LIGHTGRAY 7 • DARKGRAY 8 • LIGHTBLUE 9 • LIGHTGREEN 10 • LIGHTCYAN 11 • LIGHTRED 12 • LIGHTMAGENTA 13 • YELLOW 14 • WHITE 15
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/* setcolor() function change the current drawing color in graphic mode. */ #include<stdio.h> #include<conio.h> #include<graphics.h> void main() { int gd=DETECT,gm; initgraph(&gd,&gm," "); setbkcolor(5);//set background color setcolor(11);//color of time settextstyle(4, HORIZ_DIR, 8);//font of time setcolor(GREEN); circle(320,240,100); setcolor(RED); outtextxy(320,80."It is circle"); getch(); closegraph(); }
settextstyle() Function in C++
Settextstyle function is used to change the way in which text appears, using it we can modify the size of text, change direction of text and change the font of text. settextstyle sets the text font, the direction in which text is displayed, and the size of the characters. A call to settextstyle affects all text output by outtext and outtextxy.
Syntax for settextstyle() Function in C++
#include <graphics.h> void settextstyle(int font, int direction, int charsize);
font
One 8x8 bit-mapped font and several "stroked" fonts are available. The 8x8 bit-mapped font is the default. The enumeration font_names, which is defined in graphics.h, provides names for these different font settings: • DEFAULT_FONT – 0 8x8 bit-mapped font • TRIPLEX_FONT – 1 Stroked triplex font • SMALL_FONT – 2 Stroked small font • SANS_SERIF_FONT – 3 Stroked sans-serif font • GOTHIC_FONT – 4 Stroked gothic font • SCRIPT_FONT – 5 Stroked script font • SIMPLEX_FONT – 6 Stroked triplex script font • TRIPLEX_SCR_FONT – 7 Stroked triplex script font • COMPLEX_FONT – 8 Stroked complex font • EUROPEAN_FONT – 9 Stroked European font • BOLD_FONT – 10 Stroked bold font The default bit-mapped font is built into the graphics system. Stroked fonts are stored in *.CHR disk files, and only one at a time is kept in memory. Therefore, when you select a stroked font (different from the last selected stroked font), the corresponding *.CHR file must be loaded from disk. To avoid this loading when several stroked fonts are used, you can link font files into your program. Do this by converting them into object files with the BGIOBJ utility, then registering them through registerbgifont.
direction
Font directions supported are horizontal text (left to right) and vertical text (rotated 90 degrees counterclockwise). The default direction is HORIZ_DIR. The size of each character can be magnified using the charsize factor. If charsize is nonzero, it can affect bit-mapped or stroked characters. A charsize value of 0 can be used only with stroked fonts.
charsize
• If charsize equals 1, outtext and outtextxy displays characters from the 8x8 bit-mapped font in an 8x8 pixel rectangle onscreen. • If charsize equals 2, these output functions display characters from the 8x8 bit-mapped font in a 16*16 pixel rectangle, and so on (up to a limit of ten times the normal size). • When charsize equals 0, the output functions outtext and outtextxy magnify the stroked font text using either the default character magnification factor (4) or the user-defined character size given by setusercharsize. Always use textheight and textwidth to determine the actual dimensions of the text. This function needs to be called before the outtextxy() function, otherwise there will be no effect on text and output will be the same.
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/* settextstyle() function sets the current text font, direction and character size. All calls to outtext() and outtextxy() are affected by the new settings. */ int main() { int gm, gd; gd = VGA; gm = VGAHI; initgraph(&gd, &gm, ""); settextstyle(SANS_SERIF_FONT, HORIZ_DIR, 4); outtextxy(32, 8, "SANS_SERIF_FONT"); settextstyle(DEFAULT_FONT, HORIZ_DIR, 4); outtextxy(32, 58, "DEFAULT_FONT"); settextstyle(GOTHIC_FONT, HORIZ_DIR, 4); outtextxy(32, 108, "GOTHIC_FONT"); settextstyle(SCRIPT_FONT, HORIZ_DIR, 4); outtextxy(32, 158, "SCRIPT_FONT"); getch(); closegraph(); }
For Loop Statement in C++
In computer programming, loops are used to repeat a block of code. For example, when you are displaying number from 1 to 100 you may want set the value of a variable to 1 and display it 100 times, increasing its value by 1 on each loop iteration. When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop. A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.
Syntax of For Loop Statement in C++
for (initialization; condition; update) { // body of-loop }
initialization
initializes variables and is executed only once.
condition
if true, the body of for loop is executed, if false, the for loop is terminated.
update
updates the value of initialized variables and again checks the condition. A new range-based for loop was introduced to work with collections such as arrays and vectors.
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/* For Loop Statement in C++ Language */ // C++ program to find the sum of first n natural numbers // positive integers such as 1,2,3,...n are known as natural numbers #include <iostream> using namespace std; int main() { int num, sum; sum = 0; cout << "Enter a positive integer: "; cin >> num; for (int i = 1; i <= num; ++i) { sum += i; } cout << "Sum = " << sum << endl; return 0; }
outtextxy() Function in C++
outtextxy displays a text string in the viewport at the given position (x, y), using the current justification settings and the current font, direction, and size. To maintain code compatibility when using several fonts, use textwidth and textheight to determine the dimensions of the string. If a string is printed with the default font using outtext or outtextxy, any part of the string that extends outside the current viewport is truncated. outtextxy is for use in graphics mode; it will not work in text mode.
Syntax for outtextxy() Function in C++
#include <graphics.h> void outtextxy(int x, int y, char *string);
x
x-coordinate of the point
y
y-coordinate of the point
string
string to be displayed where, x, y are coordinates of the point and, third argument contains the address of string to be displayed. This function does not return any value.
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/* outtextxy() function displays the text or string at a specified point (x, y) on the screen. */ // C++ Implementation for outtextxy() #include <graphics.h> int main() { textcolor(RED); cleardevice(); setcolor(RED); outtextxy(150,205,"Enter the Username:"); outtextxy(150,245,"Enter the Password:"); outtextxy(150,355,"Thank you"); outtextxy(150,445,"nice job"); outtextxy(50,105,"good day"); outtextxy(50,145,"pan"); outtextxy(50,255,"go"); outtextxy(50,245,"nice day"); return 0; }
Assignment Operators in C++
As the name already suggests, these operators help in assigning values to variables. These operators help us in allocating a particular value to the operands. The main simple assignment operator is '='. We have to be sure that both the left and right sides of the operator must have the same data type. We have different levels of operators. Assignment operators are used to assign the value, variable and function to another variable. Assignment operators in C are some of the C Programming Operator, which are useful to assign the values to the declared variables. Let's discuss the various types of the assignment operators such as =, +=, -=, /=, *= and %=. The following table lists the assignment operators supported by the C language:
=
Simple assignment operator. Assigns values from right side operands to left side operand
+=
Add AND assignment operator. It adds the right operand to the left operand and assign the result to the left operand.
-=
Subtract AND assignment operator. It subtracts the right operand from the left operand and assigns the result to the left operand.
*=
Multiply AND assignment operator. It multiplies the right operand with the left operand and assigns the result to the left operand.
/=
Divide AND assignment operator. It divides the left operand with the right operand and assigns the result to the left operand.
%=
Modulus AND assignment operator. It takes modulus using two operands and assigns the result to the left operand.
<<=
Left shift AND assignment operator.
>>=
Right shift AND assignment operator.
&=
Bitwise AND assignment operator.
^=
Bitwise exclusive OR and assignment operator.
|=
Bitwise inclusive OR and assignment operator.
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/* Assignment operators are used to assigning value to a variable. The left side operand of the assignment operator is a variable and right side operand of the assignment operator is a value. The value on the right side must be of the same data-type of the variable on the left side otherwise the compiler will raise an error. */ // C++ program to demonstrate working of Assignment operators #include <iostream> using namespace std; int main() { // Assigning value 10 to a // using "=" operator int a = 10; cout << "Value of a is "<<a<<"\n"; // Assigning value by adding 10 to a // using "+=" operator a += 10; cout << "Value of a is "<<a<<"\n"; // Assigning value by subtracting 10 from a // using "-=" operator a -= 10; cout << "Value of a is "<<a<<"\n"; // Assigning value by multiplying 10 to a // using "*=" operator a *= 10; cout << "Value of a is "<<a<<"\n"; // Assigning value by dividing 10 from a // using "/=" operator a /= 10; cout << "Value of a is "<<a<<"\n"; return 0; }
exit() Function in C++
The exit function terminates the program normally. Automatic objects are not destroyed, but static objects are. Then, all functions registered with atexit are called in the opposite order of registration. The code is returned to the operating system. An exit code of 0 or EXIT_SUCCESS means successful completion. If code is EXIT_FAILURE, an indication of program failure is returned to the operating system. Other values of code are implementation-defined.
Syntax for exit() Function in C++
void exit (int status);
status
Status code. If this is 0 or EXIT_SUCCESS, it indicates success. If it is EXIT_FAILURE, it indicates failure. Calls all functions registered with the atexit() function, and destroys C++ objects with static storage duration, all in last-in-first-out (LIFO) order. C++ objects with static storage duration are destroyed in the reverse order of the completion of their constructor. (Automatic objects are not destroyed as a result of calling exit().) Functions registered with atexit() are called in the reverse order of their registration. A function registered with atexit(), before an object obj1 of static storage duration is initialized, will not be called until obj1's destruction has completed. A function registered with atexit(), after an object obj2 of static storage duration is initialized, will be called before obj2's destruction starts. Normal program termination performs the following (in the same order): • Objects associated with the current thread with thread storage duration are destroyed (C++11 only). • Objects with static storage duration are destroyed (C++) and functions registered with atexit are called. • All C streams (open with functions in <cstdio>) are closed (and flushed, if buffered), and all files created with tmpfile are removed. • Control is returned to the host environment. Note that objects with automatic storage are not destroyed by calling exit (C++). If status is zero or EXIT_SUCCESS, a successful termination status is returned to the host environment. If status is EXIT_FAILURE, an unsuccessful termination status is returned to the host environment. Otherwise, the status returned depends on the system and library implementation. Flushes all buffers, and closes all open files. All files opened with tmpfile() are deleted. Returns control to the host environment from the program. exit() returns no values.
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/* terminate the process normally, performing the regular cleanup for terminating programs by exit() function code example */ #include<iostream> using namespace std; int main() { int i; cout<<"Enter a non-zero value: "; //user input cin>>i; if(i) // checks whether the user input is non-zero or not { cout<<"Valid input.\n"; } else { cout<<"ERROR!"; //the program exists if the value is 0 exit(0); } cout<<"The input was : "<<i; }
Standard Library malloc() Function in C++
Allocate memory block. Allocates a block of size bytes of memory, returning a pointer to the beginning of the block. The content of the newly allocated block of memory is not initialized, remaining with indeterminate values. If size is zero, the return value depends on the particular library implementation (it may or may not be a null pointer), but the returned pointer shall not be dereferenced. Malloc function in C++ is used to allocate a specified size of the block of memory dynamically uninitialized. It allocates the memory to the variable on the heap and returns the void pointer pointing to the beginning address of the memory block. The values in the memory block allocated remain uninitialized and indeterminate. In case the size specified in the function is zero then pointer returned must not be dereferenced as it can be a null pointer, and in this case, behavior depends on particular library implementation. When a memory block is allocated dynamically memory is allocated on the heap but the pointer is allocated to the stack.
Syntax for malloc() Function in C++
#include <cstdlib> void* malloc (size_t size);
size
Size of the memory block, in bytes. size_t is an unsigned integral type. On success, a pointer to the memory block allocated by the function. The type of this pointer is always void*, which can be cast to the desired type of data pointer in order to be dereferenceable. If the function failed to allocate the requested block of memory, a null pointer is returned.
Advantages of malloc() in C++
There are a lot of advantages to using the malloc method in one's application: • Dynamic Memory allocation: Usually we create arrays at compile time in C++, the size of such arrays is fixed. In the case at run time we do not use all the space or extra space is required for more elements to be inserted in the array, then this leads to improper memory management or segmentation fault error. • Heap memory: Local arrays that are defined at compile time are allocated on the stack, which has lagged in memory management in case the number of data increases. Thus one needs to allocate memory out of the stack, thus malloc comes into the picture as it allocates the memory location on the heap and returns a pointer on the stack pointing to the starting address of the array type memory being allocated. • Variable-length array: This function helps to allocate memory for an array whose size can be defined at the runtime. Thus one can create the number of blocks as much as required at run time. • Better lifetime: Variable created using malloc method is proved to have a better life than the local arrays as a lifetime of local arrays depends on the scope they are being defined and cannot access out of their scope. But variables or arrays created using malloc exist till they are freed. This is of great importance for various data structures such as linked list, binary heap, etc.
Differences between the malloc() and new
• The new operator constructs an object, i.e., it calls the constructor to initialize an object while malloc() function does not call the constructor. The new operator invokes the constructor, and the delete operator invokes the destructor to destroy the object. This is the biggest difference between the malloc() and new. • The new is an operator, while malloc() is a predefined function in the stdlib header file. • The operator new can be overloaded while the malloc() function cannot be overloaded. • If the sufficient memory is not available in a heap, then the new operator will throw an exception while the malloc() function returns a NULL pointer. • In the new operator, we need to specify the number of objects to be allocated while in malloc() function, we need to specify the number of bytes to be allocated. • In the case of a new operator, we have to use the delete operator to deallocate the memory. But in the case of malloc() function, we have to use the free() function to deallocate the memory.
Data races
Only the storage referenced by the returned pointer is modified. No other storage locations are accessed by the call. If the function reuses the same unit of storage released by a deallocation function (such as free or realloc), the functions are synchronized in such a way that the deallocation happens entirely before the next allocation.
Exceptions
No-throw guarantee: this function never throws exceptions.
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/* allocate the requested size of bytes and it returns a pointer to the first byte of allocated memory by malloc() function code example. */ #include <iostream> #include <cstdlib> using namespace std; int main() { // allocate 5 int memory blocks int* ptr = (int*) malloc(5 * sizeof(int)); // check if memory has been allocated successfully if (!ptr) { cout << "Memory Allocation Failed"; exit(1); } cout << "Initializing values..." << endl << endl; for (int i = 0; i < 5; i++) { ptr[i] = i * 2 + 1; } cout << "Initialized values" << endl; // print the values in allocated memories for (int i = 0; i < 5; i++) { // ptr[i] and *(ptr+i) can be used interchangeably cout << *(ptr + i) << endl; } // deallocate memory free(ptr); return 0; }
circle() Function in C++
This library function is declared in graphics.h and used to draw a circle; it takes centre point coordinates and radius. Circle function is used to draw a circle with center (x,y) and third parameter specifies the radius of the circle. The code given below draws a circle. Where, (x, y) is center of the circle. 'radius' is the Radius of the circle.
Syntax for circle() Function in C++
#include <graphics.h> circle(x, y, radius);
x
X-coordinate of the circle
y
Y-coordinate of the circle
radius
radius of the circle This function does not return any value.
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/* draw a circle with center (x,y) and third parameter specifies the radius of the circle by circle() function code example. */ int gd=DETECT,gm=0,col=0,dol=600; initgraph(&gd,&gm,"c:/tc/bgi"); settextstyle(10,HORIZ_DIR,1); outtextxy(30,30,""); settextstyle(11,HORIZ_DIR,1); settextstyle(10,HORIZ_DIR,1); outtextxy(30,200,"Hit ENTER to Start the Magic..."); settextstyle(12,HORIZ_DIR,1); getch(); cleardevice(); while(!kbhit()) { for(int j=0;j<=50;j++) { { setcolor(2); circle(col,100,50+j); setfillstyle(4,2); floodfill(col,100,2); delay(3); col++; if(col>=600) col=0; }
imagesize() Function in C++
The header file graphics.h contains imagesize() function which returns the number of bytes required to store a bit-image. This function is used when we are using getimage. imagesize() function returns the required memory area to store an image in bytes. imagesize() function returns the number of bytes needed to store the top-left corner of the screen at left, top and the bottom-right corner at right, bottom. This function is usually used in conjunction with the getimage() function. The imagesize() function only works in graphics mode.
Syntax for imagesize() Function in C++
unsigned int imagesize(int left, int top, int right, int bottom);
left
X coordinate of top left corner
top
Y coordinate of top left corner
right
X coordinate of bottom right corner
bottom
Y coordinate of bottom right corner left, top, right, and bottom define the area of the screen in which image is stored.
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/* imagesize() function returns the number of bytes required to store a bitimage. */ /* get the number of bytes required to store a bit-image by imagesize() function code example. */ #include <graphics.h> #include <stdio.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm, color, bytes; char arr[100]; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // Draws a circle with center at // (200, 200) and radius as 50. circle(200, 200, 50); // draws a line with 2 points line(150, 200, 250, 200); // draws a line with 2 points line(200, 150, 200, 250); // imagesize function bytes = imagesize(150, 150, 250, 250); // sprintf stands for "String print". // Instead of printing on console, // it store output on char buffer // which are specified in sprintf sprintf(arr, "Number of bytes required " "to store required area = %d", bytes); // outtext function displays text // at current position. outtextxy(20, 280, arr); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }
cleardevice() Function in C++
The header file graphics.h contains cleardevice() function. cleardevice() is a function which is used to clear the screen by filling the whole screen with the current background color. It means that cleardevice() function is used to clear the whole screen with the current background color and it also sets the current position to (0,0). Both clrscr() and cleardevice() functions are used to clear the screen but clrscr() is used in text mode and cleardevice function is used in the graphics mode.
Syntax for cleardevice() Function in C++
#include <graphics.h> void cleardevice();
Clearing the screen is always an issue for developers, because now and then we want to show the user some useful or important data, which should be highlighted or at least have user's attention. It is important to note that, after clearing the device, we will lose all our drawing, shapes or images. It is useful but be little cautious. This function does not return any value.
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/* cleardevice erases (that is, fills with the current background color) the entire graphics screen and moves the CP (current position) to home (0,0). */ #include <graphics.h> int main() { clrscr(); cleardevice(); int flag=44; setbkcolor(3); draw(); char m[20]; char a[20][20]={"2xqwer4fgi","trewq9y3ry","yuip7qtgfm","jpiuy9bph6","klkjh6decc", "etlhjklo2k","lasdfapl4z","efghjv5qy","mmjnhlmt8t","134rfvup5n"}; randomize(); int r=random(10)+1; settextstyle(SCRIPT_FONT, HORIZ_DIR, 5); outtextxy(190,0,"level 8"); line(190,60, 300, 60); settextstyle(SCRIPT_FONT, HORIZ_DIR, 3); outtextxy(0,100,"\nplease this is the last time!!!"); cout<<endl<<endl<<endl<<endl<<endl<<endl<<endl<<endl<<endl<<"\t"; for(int i=0;a[r][i]!='\0';i++) { cout<<a[r][i]; td(); cout<<" "; td(); } clrscr(); cleardevice(); return 0; }
sprintf() Function in C++
Write formatted data to string. Composes a string with the same text that would be printed if format was used on printf, but instead of being printed, the content is stored as a C string in the buffer pointed by str. The size of the buffer should be large enough to contain the entire resulting string (see snprintf for a safer version). A terminating null character is automatically appended after the content. After the format parameter, the function expects at least as many additional arguments as needed for format.
Syntax for sprintf() Function in C++
#include <cstdio> int sprintf ( char * str, const char * format, ... );
str
Pointer to a buffer where the resulting C-string is stored. The buffer should be large enough to contain the resulting string.
format
C string that contains a format string that follows the same specifications as format in printf (see printf for details).
... (additional arguments)
Depending on the format string, the function may expect a sequence of additional arguments, each containing a value to be used to replace a format specifier in the format string (or a pointer to a storage location, for n). There should be at least as many of these arguments as the number of values specified in the format specifiers. Additional arguments are ignored by the function. On success, the total number of characters written is returned. This count does not include the additional null-character automatically appended at the end of the string. On failure, a negative number is returned. The format parameter of printf() can contain format specifiers that begin with %. These specifiers are replaced by the values of respective variables that follow the format string.
flags
one or more flags that modifies the conversion behavior (optional)
-
Left-justify within the given field width; Right justification is the default (see width sub-specifier).
+
Forces to preceed the result with a plus or minus sign (+ or -) even for positive numbers. By default, only negative numbers are preceded with a - sign.
(space)
If no sign is going to be written, a blank space is inserted before the value.
#
Used with o, x or X specifiers the value is preceeded with 0, 0x or 0X respectively for values different than zero. Used with a, A, e, E, f, F, g or G it forces the written output to contain a decimal point even if no more digits follow. By default, if no digits follow, no decimal point is written.
0
Left-pads the number with zeroes (0) instead of spaces when padding is specified (see width sub-specifier).
width
an optional * or integer value used to specify minimum width field.
(number)
Minimum number of characters to be printed. If the value to be printed is shorter than this number, the result is padded with blank spaces. The value is not truncated even if the result is larger.
*
The width is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted.
.precision
an optional field consisting of a . followed by * or integer or nothing to specify the precision.
.number
For integer specifiers (d, i, o, u, x, X): precision specifies the minimum number of digits to be written. If the value to be written is shorter than this number, the result is padded with leading zeros. The value is not truncated even if the result is longer. A precision of 0 means that no character is written for the value 0. For a, A, e, E, f and F specifiers: this is the number of digits to be printed after the decimal point (by default, this is 6). For g and G specifiers: This is the maximum number of significant digits to be printed. For s: this is the maximum number of characters to be printed. By default all characters are printed until the ending null character is encountered. If the period is specified without an explicit value for precision, 0 is assumed.
.*
The precision is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted.
length
an optional length modifier that specifies the size of the argument.
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/* The sprintf() function in C++ is used to write a formatted string to character string buffer. It is defined in the cstdio header file. */ /* Write formatted data to string by sprintf() function code example */ #include <cstdio> #include <iostream> using namespace std; int main() { char buffer[100]; int count; char name[] = "Max"; int age = 23; // write combination of strings and variables to buffer variable // store the number of characters written in count count = sprintf(buffer, "Hi, I am %s and I am %d years old", name, age); // print the string buffer cout << buffer << endl; // print the number of characters written cout << "Number of characters written = " << count; return 0; }


C++ Program to generate N passwords each of 'length M'. Problem focuses on finding the N permutations each of length M. Generates random number between 1 and 10. Enter the