C++ Programming Code Examples

/* Simple Calculator */ #include"stdio.h" #include"conio.h" #include"dos.h" #include"stdlib.h" #include"string.h" void DISPNUM(char *); void main() { clrscr(); _setcursortype(0); gotoxy(30,19); textcolor(GREEN+BLINK); cprintf("SIMPLE CALCULATOR"); gotoxy(50,21); textcolor(BLUE+BLINK); cprintf("HELLO WORLD"); getch(); // clrscr(); int x=30,y=10; textcolor(WHITE); gotoxy(x,y); cprintf("7 8 9"); gotoxy(x,y+2); cprintf("4 5 6"); gotoxy(x,y+4); cprintf("1 2 3"); gotoxy(x,y+6); cprintf("0"); textcolor(RED); gotoxy(x+5,y+6); cprintf(". ="); textcolor(GREEN); x=x+15; gotoxy(x,y); cprintf("/"); gotoxy(x,y+2); cprintf("*"); gotoxy(x,y+4); cprintf("-"); gotoxy(x,y+6); cprintf("+"); //Draw The For Calc// x=28;y=5; gotoxy(x,y); textcolor(WHITE); // Ú & ¿ // cprintf("%c",218); gotoxy(28+20,y); cprintf("%c",191); // Ú & ¿ // //Horiz. Boundary for(x=29;x<=28+19;x++) { gotoxy(x,y); cprintf("%c",196); gotoxy(x,y+12); cprintf("%c",196); } //End of Horiz. Bound // Ù & À // cprintf("%c",217); x=28;y=y+12; gotoxy(x,y); cprintf("%c",192); //End of Ù & À // //Vertic. Bound. for(y=6;y<=16;y++) { gotoxy(x,y); cprintf("%c",179); gotoxy(x+20,y); cprintf("%c",179); } //End of Vertic Bou. y=6; for(x=30;x<=30+16;x++) { gotoxy(x,y); cprintf("%c",196); gotoxy(x,y+2); cprintf("%c",196); } gotoxy(30,y+1); cprintf("%c %c",179,179); gotoxy(30,y); cprintf("%c",218); gotoxy(30+16,y); cprintf("%c",191); gotoxy(30,y+2); cprintf("%c",192); gotoxy(30+16,y+2); cprintf("%c",217); //End of Vertic Bound. //OutPut at X=30,Y=8// char ch; char operand1[15]="",operand2[15]="",BLANK[15]=" "; char operator1,first='y'; long double num1=0,num2=0; int i=0,ERROR=0; //Digits int MAX=10; DISPNUM(0); do { ch=getch(); if(ch=='x1b') { for(int i=1000;i>=200;i=i-50) { sound(i); delay(100); } nosound(); break; } //Numeric// if((ch>='0')&&(ch<='9')) { if(i<MAX) { if(first=='y') { operand1[i]=ch; DISPNUM(operand1); i++; } else { operand2[i]=ch; DISPNUM(operand2); i++; } } else //More than 8 digit { ERROR=1; } } else if(ch=='.') { if(first=='y') { if(strchr(operand1,'.')==NULL) { operand1[i]=ch; i++; } DISPNUM(operand1); } else { if(strchr(operand2,'.')==NULL) { operand2[i]=ch; i++; } DISPNUM(operand2); } } //Non Numeric else if (ch=='*') { operator1='*'; first='n'; i=0; } else if (ch=='/') { operator1='/'; first='n'; i=0; } else if (ch=='+') { operator1='+'; first='n'; i=0; } else if (ch=='-') { operator1='-'; first='n'; i=0; } else if ((ch=='=')||(ch==' ')) { //Store in Floating if(strcmpi(operand1,BLANK)!=0) { num1=_atold(operand1); } if(strcmpi(operand2,BLANK)!=0) { num2=_atold(operand2); } //Now Calculate switch (operator1) { case '+': num1=num1+num2; break; case '-': num1=num1-num2; break; case '*': num1=num1*num2; break; case '/': num1=num1/num2; break; } //ltoa(num1,operand1,10); gcvt(num1,12,operand1); DISPNUM(operand1); i=0; first='y'; strcpy(operand1,BLANK); strcpy(operand2,BLANK); } else //Invalid Choice { ERROR=1; } //Beep On ERROR else ------ // if (ERROR==0) { sound(920); } else { sound(100); ERROR=0; } delay(250); nosound(); gotoxy(1,1); cprintf("%d",i); }while(1); // clrscr(); gotoxy(30,19); textcolor(GREEN+BLINK); cprintf("SIMPLE CALCULATOR"); gotoxy(50,21); textcolor(BLUE+BLINK); cprintf("HELLO WORLD"); // getch(); } void DISPNUM(char *num) { textbackground(RED); gotoxy(31,7); cprintf(" "); gotoxy(31,7); cprintf("%s",num); }

/* In C++ programming, the background of the output screen is black and text color is in white color. We can color both the background and text color in the output screen. */ void office::of_beg() { int i, v; do{ textbackground(BLUE); textcolor(CYAN); _setcursortype(_NORMALCURSOR); clrscr(); for(i=0;i<10;++i) { box(1+7*i,1+2*i,4,4); delay(80); box(1+7*i,1+2*i,4,4,int(' ')); } box(74,22,4,4); gotoxy(25,2); textcolor(GREEN); cputs("WELCOME TO CREEPER OFFICE..."); gotoxy(6,6); textcolor(CYAN); cout<<"1. CALCULATOR"; gotoxy(6,12); cout<<"0. MAIN MENU"; gotoxy(6,8); cout<<"2. CREEPER FILE EXPERT "; gotoxy(6,10); cout<<"3. CALENDAR "; gotoxy(25,22); cout<<"ENTER THE CHOICE NUMBER : "; v=int(getche()-48); delay(100); if(v) { switch(v) { case 1: calc(); break; case 2: class File a; break; case 3: calendar(); break; default: gotoxy(55,22); cputs("INVALID ENTRY"); delay(1000); break; } } }while(v!=0); }

/* The operator ! is the C++ operator for the Boolean operation NOT. It has only one operand, to its right, and inverts it, producing false if its operand is true, and true if its operand is false. Basically, it returns the opposite Boolean value of evaluating its operand. The logical operators && and || are used when evaluating two expressions to obtain a single relational result. The operator && corresponds to the Boolean logical operation AND, which yields true if both its operands are true, and false otherwise. */ #include <iostream> using namespace std; main() { int a = 5; int b = 20; int c ; if(a && b) { cout << "Line 1 - Condition is true"<< endl ; } if(a || b) { cout << "Line 2 - Condition is true"<< endl ; } /* Let's change the values of a and b */ a = 0; b = 10; if(a && b) { cout << "Line 3 - Condition is true"<< endl ; } else { cout << "Line 4 - Condition is not true"<< endl ; } if(!(a && b)) { cout << "Line 5 - Condition is true"<< endl ; } return 0; }

/* 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; }

/* 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; }

/* In C++ programming, the background of the output screen is black and text color is in white color. We can color both the background and text color in the output screen. */ #include <stdio.h> #include <iostream> #include <conio.h> //this should be enough I guess using namespace std; string a; int main() { clrscr(); textcolor(2); gotoxy(3,3); textattr(4); cout << "This should be underlined?"; cout << endl; cout << "Wanna end this program? Press a key (Y) and then press enter.."; cin >> a; }

/* 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; }

/* 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; }

/* strcmpi compares string1 and string2 without sensitivity to case. All alphabetic characters in the two arguments string1 and string2 are converted to lowercase before the comparison. The function operates on null-ended strings. The string arguments to the function are expected to contain a null character (\0) marking the end of the string. */ /* function strcmpi() code example to compare strings ignoring case. */ #include <stdio.h> #include <string.h> int main(){ char str1[30]; char str2[30]; printf("Enter string1: "); fgets(str1,30,stdin); printf("Enter string2: "); fgets(str2,30,stdin); if(strcmpi(str1,str2)==0) printf("Both strings are same.\n"); else printf("Both strings are not same.\n"); return 0; }

/* 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; }

/* 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; }

/* 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; }

/* 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; }

/* 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; }

/* 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(); }

/* If strings are compared using relational operators then, their characters are compared lexicographically according to the current character traits, means it starts comparison character by character starting from the first character until the characters in both strings are equal or a NULL character is encountered. */ // CPP code example to implement relational operators on String objects #include<iostream> using namespace std; void relational_operation(string s1, string s2) { string s3 = s1 + s2; if(s1 != s2) cout << s1 << " is not equal to " << s2 << endl; if(s1 > s2) cout << s1 << " is greater than " << s2 << endl; else if(s1 < s2) cout << s1 << " is smaller than " << s2 << endl; if(s3 == s1 + s2) cout << s3 << " is equal to " << s1 + s2 << endl; } // Main function int main() { string s1("Happy"); string s2("Happy 8) Codings"); relational_operation(s1, s2); return 0; }

/* 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; }

/* copy a character string from source to destination by strcpy() string function code example */ #include <cstring> #include <iostream> using namespace std; int main() { char src[20] = "I am the source."; // large enough to store content of src char dest[30] = "I am the destination."; cout << "dest[] before copy: " << dest << endl; // copy contents of src to dest strcpy(dest,src); cout << "dest[] after copy: " << dest; return 0; }

/* strchr() function is an inbuilt function in C++ STL, which is defined in the <cstring> header file. strchr() function is used to find when the character first occurred in the string. This function returns the pointer to the location where the character first appeared in the string. If the character doesn't exist in the string the function returns the null pointer. */ /* Locate first occurrence of character in string by strchr() function code example */ #include <iostream> #include <cstring> using namespace std; int main(){ char str[] = "Happy 8) Codings"; char str_2[] = " Code Examples"; char ch_1 = 'b', ch_2 = 'T'; if (strchr(str, ch_1) != NULL){ cout << ch_1 << " " << "is present in string" << endl; } else{ cout << ch_1 << " " << "is not present in string" << endl; } if (strchr(str, ch_2) != NULL){ cout << ch_2 << " " << "is present in string" << endl; strcat(str, str_2); cout<<"String after concatenation is : "<<str; } else{ cout << ch_2 <<" " << "is not present in string" << endl; } return 0; }

/* 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 }

/* 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() }

/* 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;