The system() function is a part of the C/C++ standard library. It is used to pass the commands that can be executed in the command processor or the terminal of the operating system, and finally returns the command after it has been completed.
<stdlib.h> or <cstdlib> should be included to call this function#include <stdio.h>
int addNumbers(int a, int b); // function prototype
int main()
{
int n1,n2,sum;
printf("Enters two numbers: ");
scanf("%d %d",&n1,&n2);
sum = addNumbers(n1, n2); // function call
printf("sum = %d",sum);
return 0;
}
int addNumbers(int a, int b) // function definition
{
int result;
result = a+b;
return result; // return statement
}#include <stdio.h>
// Create a function
void myFunction() {
printf("I just got executed!\n");
}
int main() {
myFunction(); // call the function
return 0;
}
//INCLUDING BUILT-IN LIBRARIES...
#include <stdio.h>
#include <stdlib.h>
//PRE-DEFINE CONSTANT VALUES...
#define MAXNUM -12 //defining an integer
#define PI 3.1415 //defining a float
#define END "\n\n\t\tProgram has ended!!\n" //defining a string
//PRE-DEFINING CONSTANT OPERATIONS...
#define ADD(a, b, c) (a + b + c) //Operation that will add its 3 parameters
int main(){
//using other definitions to check if the current device is Windows or UNIX
#ifdef _WIN32
printf("\nWindows Operating System Detected\n");
#elif linux
printf("\nUNIX Operating System Detected\n");
#else
printf("\nOperating System could NOT be identified!\n");
#endif
printf("\nUsing pre-defined values and operations: ");
printf("\n • MAXNUM: %d",MAXNUM); //using pre-defined integer
printf("\n • PI: %f",PI); //using pre-defined float
printf("\n • ADD(): %.2f",ADD(2,5,99.5)); //using pre-defined function
printf(END); //using pre-defined string
return 0;
}#include <stdio.h>
void functionName()
{
... .. ...
... .. ...
}
int main()
{
... .. ...
... .. ...
functionName();
... .. ...
... .. ...
}