Example1-Creating a user defined function

 

#include <stdio.h>
int addition(int num1, int num2)
{
 int sum; 
 sum = num1+num2;
 return sum;
}
int main()
{
 int number1, number2; 
 printf("Enter number 1: ");
 scanf("%d",&number1);
 printf("Enter number 2: ");
 scanf("%d",&number2);
 int res = addition(number1, number2);
 printf ("Output: %d", res);
 return 0;
}

Output

 

 Enter number 1:25
 Enter number 2:55
 Output:80

 

Example2: Creating a void user defined function that doesn’t return anything

#include <stdio.h>
void introduction()
{
 printf("Welcome to CseWorld Online");
 /* There is no return statement inside this function, since its return type is void */
}
int main()
{
 introduction();
 return 0;
}

Output

Welcome to CseWorld Online