# Addition of two numbers in C

The addition of two numbers in C language is performing the arithmetic operation of adding them and printing their sum on the screen. For example, if the input is 5, 6, the output will be 11.

#include <stdio.h>

int main()
{
int x, y, z;

scanf("%d%d", &x, &y);

z = x + y;

printf("Sum of the numbers = %d\n", z);

return 0;
}

Output of the program: In the expression (z = x + y), overflow may occur if the sum is greater than the maximum value that the variable z can store.

Similarly, we can write a program that performs subtraction, multiplication, and division of two numbers.

## Addition without using third variable

#include<stdio.h>

int main()
{
int a = 1, b = 2;

/* Storing result of the addition in variable a */

a = a + b;

printf("Sum of a and b = %d\n", a);

return 0;
}

Doing this isn't recommended because the original value of the variable 'a' is lost; 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("Input 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:

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

int main()
{
long first, second, sum;

scanf("%ld%ld", &first, &second);

printf("%ld\n", sum);

return 0;
}