大数取模

#include<cstdio>
#include<cstring>
using namespace std;
const int maxn=1000+5;
int mod;
int main(){
    char in[maxn];
    while(scanf("%s%d",in,&mod)==2){
        int len=strlen(in),ans=0;
        for(int i=0;i<len;i++)
            ans=(ans*10+in[i]-'0')%mod;
        printf("%d\n",ans);
    }
}

HDU1212