#include<stdio.h>

#include<conio.h>

main()

{

int a=10, b=20; //declaration of variables.

clrscr(); //It clears the screen.

printf(“Before swap a=%d b=%d”,a,b);

a=a+b;//a=30 (10+20)

b=a-b;//b=10 (30-20)

a=a-b;//a=20 (30-10)

printf(“\nAfter swap a=%d b=%d”,a,b);

getch();

}