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C++ Programming Code Examples

C++ > Computer Graphics Code Examples

logical discription of logial errors in graphics

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/* logical discription of logial errors in graphics */ #include<iostream.h> #include<conio.h> #include<dos.h> #include<stdio.h> #include<graphics.h> #include<math.h> #include<string.h> #include<time.h> float main(void) { int*p1,*p2,*p; clock_t start,end; time_t t,t1; int z=0,z1=0; int gdriver = DETECT, gmode, errorcode; initgraph(&gdriver, &gmode, ""); int r=0; int ch,x=10,y=350; int poly[100],poly1[100],variable1; setcolor(14); ellipse(100,105,180,0,10,15); ellipse(93,125,320,50,3,7); ellipse(105,125,130,270,3,7); ellipse(110,112,250,90,3,2); line(93,128,108,133); putpixel(100,120,4); poly[0]=105; poly[1]=105; poly[2]=103; poly[3]=108; poly[4]=101; poly[5]=109; poly[6]=101; poly[7]=111; poly[8]=100; poly[9]=108; poly[10]=98; poly[11]=108; poly[12]=96; poly[13]=111; poly[14]=96; poly[15]=119; poly[16]=88; poly[17]=113; poly[18]=89; poly[19]=105; poly[20]=105; poly[21]=105; setcolor(8); drawpoly(11,poly); setfillstyle(1,8); floodfill(94,108,8); setcolor(14); poly1[0]=105; poly1[1]=105; poly1[2]=103; poly1[3]=108; poly1[4]=101; poly1[5]=109; poly1[6]=101; poly1[7]=111; poly1[8]=100; poly1[9]=108; poly1[10]=98; poly1[11]=108; poly1[12]=96; poly1[13]=111; poly1[14]=96; poly1[15]=119; drawpoly(8,poly1); line(105,105,110,105); setfillstyle(1,14); floodfill(106,110,14); floodfill(111,112,14); setcolor(2); for(variable1=0;variable1<=5;variable1+=2) ellipse(100,101,0,180,10,variable1); setcolor(4); for(variable1=0;variable1<=5;variable1+=3) ellipse(100,105,0,180,20,variable1); line(80,105,120,105); setfillstyle(1,0); fillellipse(107,111,1,2); setcolor(0); arc(107,111,70,160,3); setcolor(6); setfillstyle(1,6); fillellipse(99,112,1,3); setfillstyle(1,4); fillellipse(99,115,2,2); setcolor(8); for(variable1=0;variable1<=3;variable1++) ellipse(107,118,70,180,4,variable1); setcolor(4); line(93,128,108,133); line(108,133,110,138); line(110,138,93,133); line(93,133,93,128); setfillstyle(2,4); floodfill(96,131,4); setcolor(2); ellipse(100,193,20,70,15,60); ellipse(101,184,120,170,15,60); line(93,133,105,137); line(86,174,114,173); setfillstyle(1,2); floodfill(90,170,2); setcolor(3); line(104,140,102,150); line(94,140,94,151); line(94,140,103,140); line(100,150,108,165); line(100,165,108,165); line(94,151,100,165); setcolor(14); line(102,166,107,166); line(103,168,109,168); line(102,166,103,168); line(107,166,109,168); setfillstyle(1,14); floodfill(105,167,14); setcolor(0); line(102,169,110,169); setfillstyle(9,2); floodfill(100,145,3); setcolor(12); getimage(78,95,122,202,p1); line(108,175,106,195); line(92,175,94,195); line(108,175,92,175); line(106,195,94,195); setfillstyle(6,12); floodfill(100,180,12); setcolor(8); setfillstyle(6,8); ellipse(103,200,0,180,10,3); line(93,200,113,200); floodfill(103,199,8); getimage(78,95,122,202,p2); putimage(78,95,p2,1); putimage(78,95,p1,1); setcolor(12); setfillstyle(6,12); int po[100],pol[100]; po[0]=110; po[1]=174; po[2]=120; po[3]=196; po[4]=108; po[5]=196; po[6]=96; po[7]=174; po[8]=110; po[9]=174; drawpoly(5,po); pol[0]=96; pol[1]=174; pol[2]=89; pol[3]=174; pol[4]=87; pol[5]=196; pol[6]=97; pol[7]=196; pol[8]=101; pol[9]=184; drawpoly(5,pol); floodfill(103,177,12); floodfill(93,177,12); setcolor(8); setfillstyle(6,8); ellipse(119,200,0,180,10,3); ellipse(97,200,0,180,10,3); line(109,200,129,200); line(107,200,87,200); floodfill(119,199,8); floodfill(97,199,8); getimage(78,95,130,202,p1); putimage(78,95,p1,1); putimage(x-5,350,p1,1); setcolor(15); rectangle(0,458,getmaxx()+10,getmaxy()); setfillstyle(6,15); floodfill(10,464,15); setfillstyle(6,15); fillellipse(400,100,60,40); int v=0,v1=0,v2[1000],l1,l2,l3; int w1=0,w2,w3=20,w4; here1: delay(90); setcolor(0); setfillstyle(1,10); w2=sqrt(abs(w3*w3-w1*w1)); fillellipse(w1,w2,w3,w3); w1++; if(w1==getmaxx()+12) w1=0; while(kbhit()) ch=getch(); if(ch== 77) { x=x+5; //sound(3000); } else if (ch== 72) { v=350; for(int i=y,j=y-200,k=y+107;i>=y-200;i-=4,j+=4,k--) { if(i>=250) { if(x%2==0) { //sound(i+100); if(w1==getmaxx()+12) w1=0; fillellipse(w1,w2,w3,w3); w1++; delay(15); if(i==y) putimage(x,i+4,p1,1); putimage(x,i+4,p1,1); putimage(x,i,p1,2); if(!kbhit()) z = 10; while(kbhit()) { z+=2; if (z>100)break; v2[i]=getch(); delay(15); switch(v2[i]) { case 77: x=x+10; putimage(x,i,p1,1); putimage(x-10,i,p1,1); break; case 75: x=x-10; putimage(x,i,p1,1); putimage(x+10,i,p1,1); break; case 32: l2=i; for(l1=x+50;l1<=getmaxx();l1++) { while(kbhit()) { int t = getch(); switch(t) { case 77: x=x+10; putimage(x,i,p1,1); putimage(x-10,i,p1,1); break; case 75: x=x-10; putimage(x,i,p1,1); putimage(x+10,i,p1,1); break; } } delay(3); setcolor(0); setfillstyle(1,4); fillellipse(l1-2,l2,5,5); if(!kbhit())ungetch(t); } default: break; case 27: goto here2; } } ungetch(v2[i]); } else { ////sound(i+100); delay(15); if(i==y) putimage(x,i+4,p2,1); putimage(x,i+4,p2,1); putimage(x,i,p2,2); if(!kbhit()) z = 10; while(kbhit()) { z+=2; if (z>100)break; v2[i]=getch(); delay(15); switch(v2[i]) { case 77: x=x+10; putimage(x,i,p2,1); putimage(x-10,i,p2,1); break; case 75: x=x-10; putimage(x,i,p2,1); putimage(x+10,i,p2,1); break; case 32: default: break; case 27: goto here2; } } ungetch(v2[i]); } } if(i<250) { if(x%2==0) { ////sound(j+100); delay(15); if(j==y) putimage(x,i-4,p,1); putimage(x,j-4,p1,1); putimage(x,j,p1,2); } else { ////sound(i+100); delay(15); if(j==y) putimage(x,i-4,p,1); putimage(x,j-4,p2,1); putimage(x,j,p2,2); } } } } else if (ch== 75) { x=x-5; ////sound(3000); } else if (ch== 27) goto here2; else goto here; if(ch==77||ch==75) { if(x%2==0) { if(r==1) { if(ch==77) putimage(x-5,y,p2,1); if(ch==75) putimage(x+5,y,p2,1); } putimage(x,y,p1,1); } else { if(r==1) { if(ch==77) putimage(x-5,y,p1,1); if(ch==75) putimage(x+5,y,p1,1); } if(r==0) putimage(x-10,350,p1,1); putimage(x,y,p2,1); } r=1; } here: nosound(); ch=0; goto here1; here2: nosound(); }
If Else If Ladder in C/C++
The if...else statement executes two different codes depending upon whether the test expression is true or false. Sometimes, a choice has to be made from more than 2 possibilities. The if...else ladder allows you to check between multiple test expressions and execute different 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 of if...else Ladder in C++
if (Condition1) { Statement1; } else if(Condition2) { Statement2; } . . . else if(ConditionN) { StatementN; } else { Default_Statement; }
In the above syntax of if-else-if, if the Condition1 is TRUE then the Statement1 will be executed and control goes to next statement in the program following if-else-if ladder. If Condition1 is FALSE then Condition2 will be checked, if Condition2 is TRUE then Statement2 will be executed and control goes to next statement in the program following if-else-if ladder. Similarly, if Condition2 is FALSE then next condition will be checked and the process continues. If all the conditions in the if-else-if ladder are evaluated to FALSE, then Default_Statement will be executed.
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/* write a C program which demonstrate use of if-else-if ladder statement */ /* Program to Print Day Names using Else If Ladder in C++*/ #include <iostream> using namespace std; int main() { int day; cout << "Enter Day Number: "; cin >> day; cout << "Day is "; if (day == 1) cout << "Sunday" << endl; else if (day == 2) cout << "Monday" << endl; else if (day == 3) cout << "Tuesday" << endl; else if (day == 4) cout << "Wednesday" << endl; else if (day == 5) cout << "Thursday" << endl; else if (day == 6) cout << "Friday" << endl; else cout << "Saturday" << endl; return 0; }
ellipse() Function in C++
Ellipse is used to draw an ellipse (x,y) are coordinates of center of the ellipse, startangle is the starting angle, end angle is the ending angle, and fifth and sixth parameters specifies the X and Y radius of the ellipse. To draw a complete ellipse strangles and end angle should be 0 and 360 respectively.
Syntax for ellipse() Function in C++
#include <graphics.h> void ellipse(int x, int y, int startangle, int endangle, int xradius, int yradius);
x
x-coordinate of center of the ellipse
y
y-coordinate of center of the ellipse
startangle
starting angle
endangle
ending angle
xradius
specifies the X radius of the ellipse
yradius
specifies the Y radius of the ellipse Making a circle and an ellipse in C can be done easily. How to do is, first initialize a graph with two parameters and a path to the "bgi" folder in your system. To make an ellipse on the screen, all we need to do is call the ellipse() function with six numbers as the coordinates of the ellipse. These six co-ordinates decide the location of the ellipse, angles, and radius from X-axis and Y-axis. We would need to include graphics.h file in your program.
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/* graphics.h library is used to include and facilitate graphical operations in program. C graphics using graphics.h functions can be used to draw different shapes, display text in different fonts, change colors and many more. Using functions of graphics.h you can make graphics programs, animations, projects and games. You can draw circles, lines, rectangles, bars and many other geometrical figures. You can change their colors using the available functions and fill them. */ /* draw an ellipse on the screen by ellipse() function code example */ #include <graphics.h> 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; // location of ellipse int x = 250, y = 200; // here is the starting angle // and end angle int start_angle = 0; int end_angle = 360; // radius from x axis and y axis int x_rad = 100; int y_rad = 50; // initgraph initializes the graphics system // by loading a graphics driver from disk initgraph(&gd, &gm, ""); // ellipse function ellipse(x, y, start_angle, end_angle, x_rad, y_rad); getch(); // closegraph function closes the graphics // mode and deallocates all memory allocated // by graphics system . closegraph(); 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; }
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; }
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; }
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(); }
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; }
ungetch() Function in C++
Push a character back onto the input stream for the console. The ungetch() function pushes the character specified by c back onto the input stream for the console. This character will be returned by the next read from the console (with getch() or getche() functions) and will be detected by the function kbhit(). Only the last character returned in this way is remembered.
Syntax for ungetch() Function in C++
#include <conio.h> int ungetch( int c );
c
specify the character Function returns the character pushed back. The ungetch() function clears the end-of-file indicator, unless the value of c is EOF.
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/* push a character back onto the input stream for the console by ungetch() function code example */ #include <stdio.h> #include <ctype.h> #include <conio.h> void main() { int c; long value; value = 0; c = getche(); while( isdigit( c ) ) { value = value*10 + c - '0'; c = getche(); } ungetch( c ); printf( "Value=%ld\n", value ); }
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(); }
putpixel() Function in C++
The header file graphics.h contains putpixel() function which plots a pixel at location (x, y) of specified color. Where, (x, y) is the location at which pixel is to be put, and color specifies the color of the pixel. To put a pixel on the screen at a particular position, calling the pixel() function is a good way. This function takes three parameters as the position of the pixel and also the color of the pixel.
Syntax for putpixel() Function in C++
#include <graphics.h> void putpixel(int x, int y, int color);
x
X coordinate of the point
y
Y coordinate of the point
color
specifies the color of the pixel To use these function in your program, we would need to include graphics.h file in your program. You should also use getch() function to make the screen freeze.
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/* putpixel() function writes a pixel to the specified position in the bitmap, using the current drawing mode and the bitmap's clipping rectangle. */ /* plot a point in the color defined by color at (x,y) by putpixel() 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; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // putpixel function putpixel(85, 35, GREEN); putpixel(30, 40, RED); putpixel(115, 50, YELLOW); putpixel(135, 50, CYAN); putpixel(45, 60, BLUE); putpixel(20, 100, WHITE); putpixel(200, 100, LIGHTBLUE); putpixel(150, 100, LIGHTGREEN); putpixel(200, 50, YELLOW); putpixel(120, 70, RED); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }
arc() Function in C++
In the C programming language, there is an option to create an arc of a circle of a given radius with a given center coordinates and degree of the arc. The arc() function is used to create an arc. This arc function is included in graphics.h library in C which contains methods that can draw figures on the output screen. The function to make an arc(), accepts five parameters for x, y co-ordinate, starting angle, end angle and radius. This will make the arc will all the values are fine. The Example below takes care of all these things as it have four arcs implemented.
Syntax for arc() Function in C++
#include <graphics.h> void arc(int x, int y, int start_angle, int end_angle, int radius);
x
x coordinate of the center of the arc
y
y coordinate of the center of the arc
start_angle
starting angle of arc
end_angle
ending angle of arc
radius
radius of the arc The header file graphics.h contains arc() function which draws an arc with center at (x, y) and given radius. start_angle is the starting point of angle and end_angle is the ending point of the angle. The value of the angle can vary from 0 to 360 degree.
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/* arc() function is used to draw an arc with center (x, y) and stangle specifies starting angle, endangle specifies the end angle and last parameter specifies the radius of the arc. arc function can also be used to draw a circle but for that starting angle and end angle should be 0 and 360 respectively. */ /* create an arc by arc() 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; // location of the arc int x = 250; int y = 250; // starting angle and ending angle // of the arc int start_angle = 155; int end_angle = 300; // radius of the arc int radius = 100; // initgraph initializes the graphics system // by loading a graphics driver from disk initgraph(&gd, &gm, ""); // arc function arc(x, y, start_angle, end_angle, radius); getch(); // closegraph function closes the graphics // mode and deallocates all memory allocated // by graphics system closegraph(); return 0; }
drawpoly() Function in C++
The header file graphics.h contains drawpoly() function which is used to draw polygons i.e. triangle, rectangle, pentagon, hexagon etc. Drawpoly draws a polygon with numpoints points, using the current line style and color.
Syntax for drawpoly() Function in C++
#include <graphics.h> void drawpoly( int num, int *polypoints );
num indicates (n+1) number of points where n is the number of vertices in a polygon, polypoints points to a sequence of (n*2) integers . Each pair of integers gives x and y coordinates of a point on the polygon. We specify (n+1) points as first point coordinates should be equal to (n+1)th to draw a complete figure. To understand more clearly we will draw a triangle using drawpoly, consider for example,the array :- int points[] = { 320, 150, 420, 300, 250, 300, 320, 150}; points array contains coordinates of triangle which are (320, 150), (420, 300) and (250, 300). Note that last point(320, 150) in array is same as first. See the program below and then its output, it will further clear your understanding.
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/* draw polygons i.e. triangle, rectangle, pentagon, hexagon etc by drawpoly() function code example. */ // C Implementation for drawpoly() function #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; // coordinates of polygon int arr[] = {320, 150, 400, 250, 250, 350, 320, 150}; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // drawpoly function drawpoly(4, arr); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }
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(); }
sqrt() Function in C++
Compute square root. Returns the square root of x. The sqrt() function in C++ returns the square root of a number. This function is defined in the cmath header file. There are various functions available in the C++ Library to calculate the square root of a number. Most prominently, sqrt is used. It takes double as an argument. The <cmath> header defines two more inbuilt functions for calculating the square root of a number (apart from sqrt) which has an argument of type float and long double. Therefore, all the functions used for calculating square root in C++ are. Mathematically, sqrt(x) = √x. Additional overloads are provided in this header (<cmath>) for the integral types: These overloads effectively cast x to a double before calculations (defined for T being any integral type). This function is also overloaded in <complex> and <valarray> (see complex sqrt and valarray sqrt).
Syntax for sqrt() Function in C++
#include <cmath> double sqrt (double x); float sqrt (float x); long double sqrt (long double x); double sqrt (T x); // additional overloads for integral types
x
Value whose square root is computed. If the argument is negative, a domain error occurs. The sqrt() function takes the following parameter: x - a non-negative number whose square root is to be computed. The sqrt() function returns the square root of the given argument If a negative argument is passed to sqrt(), domain error occurs.
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/* compute square root by sqrt() math function code example */ // C++ code to demonstrate the example of sqrt() function #include <iostream> #include <cmath> using namespace std; // main code section int main() { float x; //input the value cout<<"Enter a number: "; cin>>x; // calculate the square root float result = sqrt(x); cout<<"square root of "<<x<<" is = "<<result; cout<<endl; return 0; }
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; }
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(); }
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; }
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() }
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; }
nosound() Function in C++
The nosound() function in C language is used to stop the sound played by sound() function. The nosound() function is simply silent the system. The sound() and nosound() functions are very useful as they can create very nice music with the help of programming and our user can enjoy music during working in out the program.
Syntax for nosound() Function in C++
void nosound();
You can use the function nosound to turn off the PC speaker.
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/* you can simply silent the system by nosound() function code example. */ #include <stdio.h> //to use 'sound()', 'delay()' functions #include <dos.h> int main() { //calling the function for producing //the sound of frequency 400. sound(400); //function to delay the sound for //half of second. delay(500); //calling the function to stop the //system sound. nosound(); 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; }
fillellipse() Function in C++
Draws an ellipse using (x,y) as a center point and xradius and yradius as the horizontal and vertical axes, and fills it with the current fill color and fill pattern. The header file graphics.h contains fillellipse() function which draws and fills an ellipse with center at (x, y) and (xradius, yradius) as x and y radius of ellipse. Where, (x, y) is center of the ellipse. (xradius, yradius) are x and y radius of ellipse.
Syntax for fillellipse() Function in C++
#include <graphics.h> void fillellipse(int x, int y, int xradius, int yradius);
x
x coordinate of center of the ellipse
y
y coordinate of center of the ellipse
xradius
horizontal axes of the ellipse
yradius
vertical axes of the ellipse This function does not return any value.
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/* fillellipse() function draws an ellipse and fill it with current drawing color and pattern. */ /* draws an ellipse and fill it by fillellipse() 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, ""); // fillellipse fuction fillellipse(200, 200, 50, 90); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); 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; }
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; }
abs() Function in C++
Absolute value. Returns the absolute value of parameter n ( /n/ ). In C++, this function is also overloaded in header <cmath> for floating-point types (see cmath abs), in header <complex> for complex numbers (see complex abs), and in header <valarray> for valarrays (see valarray abs). Basically the abs function evaluates the absolute value of the given value i.e. value after removing all the signs of negative and positive from the number. Which means it will always return a positive number.
Syntax for abs() Function in C++
#include <cstdlib> int abs (int n); long int abs (long int n); long long int abs (long long int n);
n
Integral value. Function returns the absolute value of n. abs() function - In C the input is of type 'int' whereas in C++ input is of type 'int, long int or long long int'. In C the output is of 'int' type and in C++ the output has the same data type as input. Function is defined as <cstdlib> (C Standard General Utilities Library) header file. They give the exact value of integer that is input to them as their argument.
Portability
In C, only the int version exists. For the long int equivalent see labs. For the long long int equivalent see llabs.
Data races
Concurrently calling this function is safe, causing no data races.
Exceptions
No-throw guarantee, this function throws no exceptions. If the result cannot be represented by the returned type (such as abs(INT_MIN) in an implementation with two's complement signed values), it causes undefined behavior.
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/* return the absolute value of parameter by abs() function code example */ // C++ code to demonstrate the example of abs() function #include <iostream> #include <cmath> using namespace std; // main() section int main() { float x; float result; x = -10; cout<<"abs("<<x<<"): "<<abs(x)<<endl; x = -1012.232; cout<<"abs("<<x<<"): "<<abs(x)<<endl; x = 1012.232; cout<<"abs("<<x<<"): "<<abs(x)<<endl; x = -.908; cout<<"abs("<<x<<"): "<<abs(x)<<endl; return 0; }
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; }
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; }
sound() Function in C++
Our system can create various sounds on different frequencies. The sound() is very useful as it can create very nice music with the help of programming and our user can enjoy music during working in out the program. Sound function produces the sound of a specified frequency. Used for adding music to a C++ program.
Syntax for sound() Function in C++
void sound(unsigned frequency);
frequency
the frequency of the sound
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/* sound() function produces the sound of a specified frequency. */ int k; //loop to increment the value of a till 100. for ( k = 1 ; a <= 100 ; a = k++ ) { //calling the function for producing //the sound of value a. sound(a); //delay the sound 10 miliseconds. delay(10); } // function to stop the system sound. nosound(); return 0;
floodfill() Function in C++
floodfill function is used to fill an enclosed area. Current fill pattern and fill color is used to fill the area.(x, y) is any point on the screen if (x,y) lies inside the area then inside will be filled otherwise outside will be filled, border specifies the color of boundary of area. To change fill pattern and fill color use setfillstyle.
Syntax for floodfill() Function in C++
#include <graphics.h> void floodfill(int x, int y, int border_color).
x
X coordinate of the point within the enclosed area to be filled
y
Y coordinate of the point within the enclosed area to be filled
border_color
specify the color 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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/* floodfill() fills an enclosed area on bitmap devices. (x,y) is a "seed point" within the enclosed area to be filled. The area bounded by the color border is flooded with the current fill pattern and fill color. If the seed point is within an enclosed area, the inside will be filled. If the seed is outside the enclosed area, the exterior will be filled. Use fillpoly instead of floodfill whenever possible so that you can maintain code compatibility with future versions. */ /* fill an enclosed area on bitmap devices by floodfill() function code example. */ #include <stdio.h> #include <conio.h> void main() { int d,m; int midx,midy; d=DETECT; initgraph(&d,&m,"c:\\tc\\bgi"); midx=getmaxx()/2; midy=getmaxy()/2; circle(midx,midy,50); floodfill(midx,midy,15); circle(midx+50,midy+100,80); floodfill(midx,midy,15); getch(); closegraph(); }
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; }
Switch Case Statement in C++
Switch statement in C tests the value of a variable and compares it with multiple cases. Once the case match is found, a block of statements associated with that particular case is executed. Each case in a block of a switch has a different name/number which is referred to as an identifier. The value provided by the user is compared with all the cases inside the switch block until the match is found. If a case match is NOT found, then the default statement is executed, and the control goes out of the switch block.
Syntax for Switch Case Statement in C++
switch( expression ) { case value-1: Block-1; Break; case value-2: Block-2; Break; case value-n: Block-n; Break; default: Block-1; Break; } Statement-x;
• The expression can be integer expression or a character expression. • Value-1, 2, n are case labels which are used to identify each case individually. Remember that case labels should not be same as it may create a problem while executing a program. Suppose we have two cases with the same label as '1'. Then while executing the program, the case that appears first will be executed even though you want the program to execute a second case. This creates problems in the program and does not provide the desired output. • Case labels always end with a colon ( : ). Each of these cases is associated with a block. • A block is nothing but multiple statements which are grouped for a particular case. • Whenever the switch is executed, the value of test-expression is compared with all the cases which we have defined inside the switch. Suppose the test expression contains value 4. This value is compared with all the cases until case whose label four is found in the program. As soon as a case is found the block of statements associated with that particular case is executed and control goes out of the switch. • The break keyword in each case indicates the end of a particular case. If we do not put the break in each case then even though the specific case is executed, the switch in C will continue to execute all the cases until the end is reached. This should not happen; hence we always have to put break keyword in each case. Break will terminate the case once it is executed and the control will fall out of the switch. • The default case is an optional one. Whenever the value of test-expression is not matched with any of the cases inside the switch, then the default will be executed. Otherwise, it is not necessary to write default in the switch. • Once the switch is executed the control will go to the statement-x, and the execution of a program will continue.
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/* the switch statement helps in testing the equality of a variable against a set of values */ #include <iostream> using namespace std; int main () { // local variable declaration: char grade = 'D'; switch(grade) { case 'A' : cout << "Excellent!" << endl; break; case 'B' : case 'C' : cout << "Well done" << endl; break; case 'D' : cout << "You passed" << endl; break; case 'F' : cout << "Better try again" << endl; break; default : cout << "Invalid grade" << endl; } cout << "Your grade is " << grade << endl; return 0; }


To convert decimal number to binary number in C++, you have to enter the decimal number to convert it into 'binary number' to print the equivalent value in binary format as shown in
To find the frequency of character in string in C++, enter the string and enter the character to Find the Frequency of that character (or to "count the occurrence of character") in string