C program to add two numbers without using 3rd 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;
}

/*

Output :

Sum of a and b = 3
*/