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。

 1 /* UVa 424 - Integer Inquiry */
 2 # include <iostream>
 3 # include <string>
 4 # include <cstring>
 5 # include <algorithm>
 6 
 7 using namespace std;
 8 
 9 const int maxn = 105;
10 
11 struct bign{
12        int len, s[maxn];
13        bign() {memset(s, 0, sizeof(s)); len = 1;}
14        bign operator = (const char * num)
15        {
16                len = strlen(num);
17                for (int i = 0; i < len; ++i)
18                    s[i] = num[len-i-1] - '0';
19                return *this;
20        }
21        string str() const
22        {
23                  string res = "";
24                  for (int i = 0; i < len; ++i)
25                        res = (char)(s[i]+'0') + res;
26                  if (res == "") res = "0";
27                  return res;
28        }
29        bign operator + (const bign& b) const
30        {
31                 bign c;
32                 c.len = 0;
33                 for (int i = 0, g = 0; g || i < max(len, b.len); ++i)
34                 {
35                         int x = g;
36                      if (i < len) x += s[i];
37                      if (i < b.len) x += b.s[i];
38                      c.s[c.len++] = x % 10;
39                      g = x / 10;
40               }
41               return c;
42        }
43 };
44 
45 istream& operator >> (istream &in, bign& x)
46 {
47           string s;
48           in >> s;
49           x = s.c_str();
50           return in;
51 }
52 ostream& operator << (ostream &out, const bign& x)
53 {
54           out << x.str();
55           return out;
56 }
57 
58 int main()
59 {
60      bign a, sum;
61           
62      while (cin >> a)
63      {
64            if (a.len == 1 && a.s[0] == 0)
65                 break;
66            sum = sum + a;
67       }
68       cout << sum << endl;
69      
70      return 0;
71 }

一个好的大数类模板。