大数对小数的求余和商

用到了同余定理：(a+b)%c=(a%c+b%c)%c，

并在取余之前求各个位置的商；

题目：http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=1435

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int nmax=10000000;
char num1[nmax];
char num[nmax];
int main()
{

    long long b;
    char ope;
    while(~scanf("%s %c %lld",num1,&ope,&b))
    {    memset(num,sizeof(num));
        int len=strlen(num1);
        long long a=0,k=0;
        for(int i=0;i<len;i++)
        {
            a=a*10+(num1[i]-'0');
            num[k++]=a/b+'0';//取余前求商
            a%=b;
        }
        if(ope=='%') cout<<a<<endl;
        else
            {
              int i=0;
              while(num[i]=='0') i++;
              if(num[i]==0) i--;
              for(;i<k;i++) cout<<num[i];
              cout<<endl;

            }
    }
}