poj 2981 大整数加法

#include <string.h>
#include <iostream>
using namespace std;

#define MAX 200

unsigned int num[MAX+10];
unsigned int num1[MAX+10];

int main()
{
    string str1,str2;
    cin>>str1>>str2;
    memset(num,0,sizeof(num));
    memset(num1,0,sizeof(num1));
    int len = str1.length();int index = 0;
    for (int i=len-1;i>=0;i--)
    {
        num[index++] = str1[i]-'0';
    }
    len = str2.length();index = 0;
    for (int i=len-1;i>=0;i--)
    {
        num1[index++] = str2[i]-'0';
    }

    len = str1.length()>str2.length() ? str1.length() : str2.length();

    for (int i=0;i<len;i++)
    {
        num[i] += num1[i];
        if (num[i]>=10)
        {
            num[i] -= 10;
            num[i+1]++;
        }
    }
    bool flag = false;
    for (int i=len;i>=0;i--)
    {
        if (flag||num[i])
        {
            flag = true;
            cout<<num[i];
        }
    }
    if (!flag)
    {
        cout<<"0";
    }

    return 0;
}