reverse digits of a number Program

1. Direct method - 

#include <stdio.h>
int main()
{
  int a,o,t,h,th,n;
  scanf("%d",&a);
  o=a/1000;a=a%1000;
  t=a/100;a=a%100;
  h=a/10;a=a%10;
  th=a;
  printf("%d",1000*th+100*h+10*t+o);
return 0;
}

Output -

465
564

2. loop -

#include <stdio.h>
int main()
{
  int r,n,sum=0;
  scanf("%d",&n);
  while(n>0)
  {
    r=n%10;
    n=n/10;
    sum=sum*10+r;
  }
  printf("%d",sum);
return 0;
}

Output -

1234
4321