C Program to Add two Numbers using Pointer

In this article, you will learn and get code about adding of two numbers in C using pointer. So the question is, Write a program in C that adds any two number entered by user (at run-time) using pointer.

Here we will only discuss about brief explanation of pointer while adding any two number in C. To learn Pointer in detail, then refer to Pointer in C tutorial. Let's take a look at the program first, then will explain it further.

Addition using Pointer in C

To add two numbers using pointer in C programming, you have to ask from user to enter any two number, then perform the operation using pointer as shown here in the following program:

#include<stdio.h>
#include<conio.h>
int main()
{
    int num1, num2, sum;
    int *ptr1, *ptr2;
    printf("Enter any two Number: ");
    scanf("%d%d", &num1, &num2);
    ptr1 = &num1;
    ptr2 = &num2;
    sum = *ptr1 + *ptr2;
    printf("\nSum of %d and %d is %d", *ptr1, *ptr2, sum);
    getch();
    return 0;
}

This program was written under Code::Blocks IDE. Here is the initial snapshot of sample run:

Now supply any two number as input say 10 and 20 and press ENTER key to see the output as shown here in the snapshot given below:

In above program, there are two important operators. The & (ampersand) and * (star) operator. The & is called as address of operator, and * is called as value at address operator.

Program Explained

• Declare three variables say num1, num2, and sum of int (integer) type
• Here first two variable stores the two number entered by user at run-time
• And the third variable, sum will be used to store the summation of given two number using pointer
• Declare two variable say ptr1 and ptr2 of int pointer (integer pointer) type
• To declare any variable as pointer type variable, just place * (star) before the variable without including any space
• Scan two number at run-time. That is ask from user to enter any two number and keep it in num1 and num2 variable
• Initialize the address of first variable (that holds first number) num1 to ptr1 using & (address of) operator.
• Initialize the address of second variable (that holds second number) num2 to ptr2 using & (address of) operator.
• Perform the operation
  value at ptr1 + value at ptr2
  using * (value at address) operator. As both ptr1 and ptr2 holds the address of entered two number. And finally initialize it to the variable sum that holds the addition result of given two number by user
• Print the value of sum as output

Here we have initialized the address of first number to first pointer and the address of second number to second pointer, using address of (&) operator. And then, we have added the two number using value at address (*) operator, and initialized it to the variable sum. Finally printed value of sum as addition result.

Here is another program, that provides you the full understanding about pointer after watching its output carefully. Let's take a look at the program:

#include<stdio.h>
#include<conio.h>
int main()
{
    int num1, num2, sum;
    int *ptr1, *ptr2;
    printf("Enter any two Number: ");
    scanf("%d%d", &num1, &num2);
    printf("\nAddress of %d is %p", num1, &num1);
    printf("\nAddress of %d is %p", num2, &num2);
    ptr1 = &num1;
    ptr2 = &num2;
    printf("\n\nptr1 = %p", ptr1);
    printf("\nptr2 = %p", ptr2);
    printf("\n\nValue at %p is %d", ptr1, *ptr1);
    printf("\nValue at %p is %d", ptr2, *ptr2);
    sum = *ptr1 + *ptr2;
    printf("\n\nSum of %d and %d is %d", *ptr1, *ptr2, sum);
    getch();
    return 0;
}

The output of above program is shown in the snapshot given below:

The format specifier %p is used for the standard notation of memory's address.

Same Program in Other Languages

• C++ Add Two Numbers using Pointer
• Java Add two Numbers using Pointer

C Online Test