How to write program in C for swapping two numbers without using third variable?

Hello Ricky 

Check this solution. 

Use following program in c:

#include<stdio.h>
#include<conio.h>

void main()
{
       int a=3,b=4;
       clrscr();
       printf("\n Before swapping :");
       printf("\n a = %d  and  b = %d",a,b);
       a=a+b;
       b=a-b;
       a=a-b;
       printf("\n a = %d and b = %d",a,b);
       getch();
}