swapping of two numbers

#include<stdio.h>
#include<conio.h>
void main()
{
int a,b,t;
clrscr();
printf("Enter two values:\n");
scanf("%d%d",&a,&b);
printf("\n\nBefore swapping %d %d\n\n",a,b);
t=a;
a=b;
b=t;
printf("After swapping %d %d",a,b);
getch();
}

 out put : Enter two values: 1 2
                 Before swapping 1 2
                 After swapping 2 1
  
                  ( OR )

#include<stdio.h>
#include<conio.h>
void main()
{
int a,b;
clrscr();
printf("Enter two values:\n");
scanf("%d%d",&a,&b);
printf("\n\nBefore swapping %d %d\n\n",a,b);
a=a*b;
        b=a/b;
        a=a/b;
printf("After swapping %d %d",a,b);
getch();
}

 out put : Enter two values: 1 2
                 Before swapping 1 2
                 After swapping 2 1

                     ( OR )

#include<stdio.h>
#include<conio.h>
void main()
{
int a,b;
clrscr();
printf("Enter two values:\n");
scanf("%d%d",&a,&b);
printf("\n\nBefore swapping %d %d\n\n",a,b);
a=a+b;
        b=a-b;
        a=a-b;
printf("After swapping %d %d",a,b);
getch();
}

 out put : Enter two values: 1 2
                 Before swapping 1 2
                 After swapping 2 1

                      ( OR )

#include<stdio.h>
#include<conio.h>
void main()
{
int a,b;
clrscr();
printf("Enter two values:\n");
scanf("%d%d",&a,&b);
printf("\n\nBefore swapping %d %d\n\n",a,b);
b=(a+b)-(a=b);
printf("After swapping %d %d",a,b);
getch();
}

out put : Enter two values: 1 2
                Before swapping 1 2
                After swapping 2 1