Program in C to swap the three digit number

Write a program in C to swap the three digit number

#include<stdio.h>

#include<conio.h>

void main ()

{

          int b,r,n,r1,r2;

          clrscr ();

          printf ("Enter the Value: ");

          scanf ("%d",&n);

          r=n%10;

          n=n/10;

          r1=n%10;

          n=n/10;

          r2=n%10;

          n=n/10;

          b=(r*100)*(r2*10)+(r2);

          printf ("%d%d%d",r,r1,r2);

          getch ();

}