Program to find swapping of two numbers

/*Program to find swapping of two numbers*/

#include<conio.h>

#include<stdio.h>

void main()

{

     int a=10,b=20,temp;

     clrscr();

     printf("before swapping a=%d and b=%d\n",a,b);

     //temp=a;

     //a=b;

    //b=temp;

     a=a+b;

     b=a-b;

     a=a-b;

    printf("after swapping a=%d and b=%d",a,b);

    getch();

}