C Program to Add two Integers

A program to add two integers takes two numbers, performs their mathematical sum, and stores the result in another variable.

Syntax

int sum = number1 + number2;

Method 1: Adding Fixed Values

This approach demonstrates adding two predefined integer values −

#include <stdio.h>

int main() {
    int a = 545;
    int b = 123;
    int sum = a + b;
    
    printf("The first number is %d<br>", a);
    printf("The second number is %d<br>", b);
    printf("The sum of two numbers is %d<br>", sum);
    
    return 0;
}

The first number is 545
The second number is 123
The sum of two numbers is 668

Method 2: Adding User Input Values

This approach takes input from the user and calculates the sum −

#include <stdio.h>

int main() {
    int num1, num2, sum;
    
    printf("Enter first integer: ");
    scanf("%d", &num1);
    
    printf("Enter second integer: ");
    scanf("%d", &num2);
    
    sum = num1 + num2;
    
    printf("Sum of %d and %d is: %d<br>", num1, num2, sum);
    
    return 0;
}

Enter first integer: 25
Enter second integer: 35
Sum of 25 and 35 is: 60

Key Points

• The + operator performs arithmetic addition on integers
• Variables must be declared before use in C
• The scanf() function reads user input with proper format specifiers

Conclusion

Adding two integers in C is straightforward using the + operator. Both fixed values and user input methods work effectively for mathematical addition operations.