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.

#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:

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;
}