Self Numbers

http://poj.org/problem?id=1316

#include<stdio.h>
#include<string.h>
int  f[10001];
int main()
{
    int i;
    memset(f,0,sizeof(f));
    for (i = 1; i < 10001; i ++)
    {
        int n = i;
        int ans = n;
        while(n)
        {
            ans += n%10;
            n /= 10;
        }
        f[ans] = 1;
    }
    for (i = 1; i < 10001; i ++)
    {
        if (f[i]==0)
            printf("%d\n",i);
    }
    return 0;
}