Swapping without using 3rd variable in c and c++ and any language use logic

Swapping  without  using third variable in c,c++,Java,JavaScript and any language logic....

// swapping without third variable.
#include<stdio.h>
#include<conio.h>
void main(){
    int a,b;
    clrscr();
    printf("Enter the value of a=\t");
    scanf("%d",&a);
    printf("Enter the value of b=\t");
    scanf("%d",&b);
    printf("before swapping\n");
    printf("a is=%d",a);
    printf("\nb is=%d\n",b);
    a=a+b;
    b=a-b;
    a=a-b;
    printf("after swapping\n");
    printf("a is=%d\n",a);
    printf("b is=%d",b);
    getch();
}

Divanshu Sindhwani