C program to find the sum of digits of a number

#include<stdio.h>
main()
{
int r,s;
long n;
printf("Enter any number\n");
scanf("%ld",&n);
s=0;
while(n>0)
{
r=n%10;
s=s+r;
n=n/10;
}
printf("The sum of digits is %d",s);
}