Interchanging two variables without using the third one

Using less variables is a sign of good programming. Here's the example program to interchanging the values of two variables without using third variable.

Code:

#include<stdio.h>

#include<conio.h>

void main()

{

//Initialization

  int var1,var2; 

    printf("Enter two integers\n");

//Taking input from user

      printf("a = ");

      scanf("%d",&var1);

      printf("b = ");

      scanf("%d",&var2);

   var1=var1+var2;

   var2=var1-var2;

   var1=var1-var2;

    printf("a = %d\n",var1);

    printf("b = %d\n",var2);

  getch();

}

Result:

Enter two integers

a = 5

b = 11

a = 11

b = 5