C program to add two numbers using pointers

This program performs addition of two numbers using pointers. In our program we have two two integer variables x, y and two pointer variables p and q. Firstly we assign the addresses of x and y to p and q respectively and then assign the sum of x and y to variable sum. Note that & is address of operator and * is value at address operator.

C programming code

#include <stdio.h>
 
int main()
{
   int first, second, *p, *q, sum;
 
   printf("Enter two integers to add\n");
   scanf("%d%d", &first, &second);
 
   p = &first;
   q = &second;
 
   sum = *p + *q;
 
   printf("Sum of entered numbers = %d\n",sum);
 
   return 0;
}

Output of program:

C program to add numbers using call by reference

#include <stdio.h>
 
long add(long *, long *);
 
int main()
{
   long first, second, *p, *q, sum;
 
   printf("Input two integers to add\n");
   scanf("%ld%ld", &first, &second);
 
   sum = add(&first, &second);
 
   printf("(%ld) + (%ld) = (%ld)\n", first, second, sum);
 
   return 0;
}
 
long add(long *x, long *y) {
   long sum;
 
   sum = *x + *y;
 
   return sum;
}