#include<stdio.h>
#include<conio.h>
void main()
{
    int a=7,b=5;
    //clrscr();
    printf("Actual values : \n a=%d \t b=%d",a,b);
    a=a*b;
    b=a/b;
    a=a/b;
    printf("\n After Swapping : \n a=%d \t b=%d",a,b);
    getch();
}

 OUTPUT:

Actual values :
 a=7     b=5
 After Swapping :
 a=5     b=7
 

 

You can see an another method of writing the code with out using third variable.