华丽的大数类，华丽的AC：Integer Inquiry

参考《算法竞赛入门经典》（刘汝佳）中大数类的实现，终于 AC 了；

使用大数类写着感觉很轻松，AC 得也很轻松。。

不过还没找到 C 代码 WA 的原因。

/* UVa 424 - Integer Inquiry */
# include <iostream>
# include <string>
# include <cstring>
# include <algorithm>

using namespace std;

const int maxn = 105;

struct bign{
       int len, s[maxn];
       bign() {memset(s, 0, sizeof(s)); len = 1;}
       bign operator = (const char * num)
       {
               len = strlen(num);
               for (int i = 0; i < len; ++i)
                   s[i] = num[len-i-1] - '0';
               return *this;
       }
       string str() const
       {
                 string res = "";
                 for (int i = 0; i < len; ++i)
                       res = (char)(s[i]+'0') + res;
                 if (res == "") res = "0";
                 return res;
       }
       bign operator + (const bign& b) const
       {
                bign c;
                c.len = 0;
                for (int i = 0, g = 0; g || i < max(len, b.len); ++i)
                {
                        int x = g;
                     if (i < len) x += s[i];
                     if (i < b.len) x += b.s[i];
                     c.s[c.len++] = x % 10;
                     g = x / 10;
              }
              return c;
       }
};

istream& operator >> (istream &in, bign& x)
{
          string s;
          in >> s;
          x = s.c_str();
          return in;
}
ostream& operator << (ostream &out, const bign& x)
{
          out << x.str();
          return out;
}

int main()
{
     bign a, sum;
          
     while (cin >> a)
     {
           if (a.len == 1 && a.s[0] == 0)
                break;
           sum = sum + a;
      }
      cout << sum << endl;
     
     return 0;
}

一个好的大数类模板。