C program to add two numbers

C program to add two numbers: This c language program perform the basic arithmetic operation of addition on two numbers and then prints the sum on the screen. For example if the user entered two numbers as 5, 6 then 11 (5 + 6) will be printed on the screen.

C programming code

#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 entered numbers = %d\n",c);
 
   return 0;
}

Output of program:

Download Add numbers program executable.

In the expression (c = a + b) overflow may occur if sum of a and b is larger than maximum value which can be stored in variable c.

Addition without using third variable

#include<stdio.h>
 
main()
{
   int a = 1, b = 2;
 
   /* Storing result of addition in variable a */
 
   a = a + b;
 
   /** Not recommended because original value of a is lost  
    *  and you may be using it somewhere in code considering it 
    *  as it was entered by the user. 
    */
 
   printf("Sum of a and b = %d\n", a);
 
   return 0;
}

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

Adding numbers in c using 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 still larger numbers which doesn't fit in long range then use array, string or other data structure.