Addition of two numbers in C: This C language program performs the basic arithmetic operation of addition of two numbers and then prints their sum on the screen. For example, if a user will input two numbers as; '5', '6' then '11' (5 + 6) will be printed on the screen. In the expression (c = a + b) overflow may occur if the sum of a and b is larger than the maximum value which can be stored in the variable c. Similarly, you can write a C program which performs subtraction, multiplication, and division of two numbers.

## Addition program in C

#include<stdio.h> int main() { int a, b, c; printf("Enter two numbers to add\n"); scanf("%d%d", &a, &b); c = a + b; printf("Sum of the numbers = %d\n", c); return 0; }

Output of C addition program:

Download Add numbers program executable.

In the expression (c = a + b) overflow may occur if the sum of a and b is larger than the maximum value which can be stored in the variable c. Similarly, you can write a C program which performs subtraction, multiplication, and division of two numbers.

## Addition without using third variable

#include<stdio.h> main() { int a = 1, b = 2; /* Storing result of addition in variable a */ a = a + b; printf("Sum of a and b = %d\n", a); return 0; }

This method isn't recommended because the original value of the variable 'a' is lost and if we require it further in the program, then we will not have it.

## C program to add two numbers repeatedly

#include <stdio.h> int main() { int a, b, c; char ch; while (1) { printf("Inut two integers\n"); scanf("%d%d", &a, &b); getchar(); c = a + b; printf("(%d) + (%d) = (%d)\n", a, b, c); printf("Do you wish to add more numbers (y/n)\n"); scanf("%c", &ch); if (ch == 'y' || ch == 'Y') continue; else break; } return 0; }

Output of program:

Inut two integers 2 6 (2) + (6) = (8) Do you wish to add more numbers (y/n) y Inut two integers 2 -6 (2) + (-6) = (-4) Do you wish to add more numbers (y/n) y Inut two integers -5 3 (-5) + (3) = (-2) Do you wish to add more numbers (y/n) y Inut two integers -5 -6 (-5) + (-6) = (-11) Do you wish to add more numbers (y/n) n

## C program for addition of two numbers using a function

We can calculate sum of two integers using a function.

#include<stdio.h> long addition(long, long); main() { long first, second, sum; scanf("%ld%ld", &first, &second); sum = addition(first, second); printf("%ld\n", sum); return 0; } long addition(long a, long b) { long result; result = a + b; return result; }

We have used long data type as it can handle large numbers if you want to add very large numbers which don't fit in long range then use an array, a string or other suitable data structure.