C Programming language

Here first insert two values from keyboard then add these two values and store values it into one variable. Then second variable value is stored value -second value and first variable value is stored value- second variable value.

This is like

a=a+b;

b=a-b=a+b-b=a;

a=a-b=a+b-a=b;

So value of variables are sapped.

/* swap two number using two variables */

#include<stdio.h>
#include<conio.h>
void main()
{
	int a,b;
	clrscr();
	printf("Enter the two numbers\t");
	scanf("%d%d",&a,&b);
	a=a+b;
	b=a-b;
	a=a-b;
	printf("\n Swapped numbers a=%d b=%d",a,b);
	getch();
}