Reverse Number in C

#include<conio.h>
#include<stdio.h>
int main()
{
int n,a,r=0;
scanf("%d",&n);
while(n>=1)
{
a=n%10;
r=r*10+a;
n=n/10;
}
printf("res no is =%d",r);
getch();
}

Output