main()
{
int a,b,c;
printf("enter two no's :");
scanf("%d%d",&a,&b);
c=a^=b^=a^=b;
printf("%d",c);
}

void main()
{
 int a,b;
 printf("Enter two numbers\n");
  scanf("%d%d",&a,&b);
 b=a+b-(a=b);
 printf("%d %d ",a,b);
}

amaresh@Hare-Krishna:~$ cat swp.c 
#include<stdio.h>
int
main(){
        int a=5,b=6; // Compile using gcc -Wall
#ifdef DEBUG // to avoid compiler warnings
        a ^=b^=a^=b;
#endif
        printf("value of a is %d and b is %d\n",a,b);
        return 0;
}

step 1.
a=b,b=a

#include<stdio.h> 	
main()
{
 int a=5,b=9;
 printf("%d %d \n",a,b);
 a^=b^=a^=b;
 printf("%d %d \n",a,b);
}

#define SWAP(x,y) int t;t=x;x=y;y=t;

#define swap(a,b) a^=b^=a^=b;

#include(stdio.h);
#include(stdlib.h);
void main()
{
int a=10,b=20;
swap(a,b);
a=b&b=a;
printf("%d%d",a,b);
}

(a=a-(b=(a=a+b)-b));

int a=5,b=2;
printf("%d %d");


execute the pgm deftly swap wil tak place.......

#include<stdio.h>
#include<conio.h>
void main()
{
int a=5,b=2,t;
clrscr();
printf("a=%d,b=%d",a,b,b=t,a=b,t=a);
getch();
}

#include<stdio.h>
#include<conio.h>
void main()
{
int a=5,b=2,t;
clrscr();
printf("a=%d,b=%d",a,b,b=t,a=b,t=a);
getch();
}