大整数类模版(部分)

刘汝佳算法竞赛入门经典BigIngeger代码

#include <cstdio>//C语言io
#include <cstring>//以下是c语言常用头文件
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cctype>
#include <cstring>
#include <cmath>
#include <iostream>//c++IO
#include <sstream>
#include <string>
#include <list>//c++常用容器
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>//c++泛型的一些函数
#include <functional>//用来提供一些模版
#define fo0(i,n) for(int i = 0;i < n; ++i)
#define fo1(i,n) for(int i = 1;i <= n; ++i)
#define mem(ar,num) memset(ar,num,sizeof(ar))
#define me(ar) memset(ar,0,sizeof(ar))
#define lowbit(x) (x&(-x))
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
const int    prime = 999983;
const int    INF = 0x3FFFFFFF;
const LL     INFF =0x3FFFFFFFFFFFFFFF;
const double pi = acos(-1.0);
const double inf = 1e18;
const double eps = 1e-9;
const LL     mod = 1e9 + 7;
struct BigInteger{
     static const  int BASE = 100000000;
     static const int WIDTH = 8;
     vector<int> s;
     BigInteger(long long num = 0){*this = num;}
     BigInteger operator = (long long num )//由一个long long 型的值直接复制给BigInterger
     {
        s.clear();
        do{
            s.push_back(num%BASE);
            num /= BASE;
        } while(num>0);
        return *this;
     }
     BigInteger operator = (const string &str)//由一个字符串转换为BIginterger

     {
         s.clear();
         int x,len = (str.length()-1)/WIDTH+1;//这样做是为了0-8是一种情况9 - 16是一种情况
         for(int i = 0; i < len;++i)
         {
             int End = str.length()-i*WIDTH;
             int start = max(0,End-WIDTH);
             sscanf(str.substr(start,End-start).c_str(),"%d",&x);
             s.push_back(x);
          }
          return *this;
     }
     bool operator < (const BigInteger &b)
     {
         if(s.size()!=b.s.size())
            return s.size()<b.s.size();
         for(int i = s.size()-1;i >= 0; --i)
         {
             if(s[i]!=b.s[i])
                return s[i]<b.s[i];
         }
     }
     bool operator >(const BigInteger &b)
     {
         return !(*this < b);
     }

};
ostream &operator<<(ostream &out,const BigInteger &x)
{
    out<<x.s.back();
    for(int i = x.s.size()-2;i >= 0;i --)
    {
        char buf[20];
        sprintf(buf,"%08d",x.s[i]);
        for(int j = 0;j < strlen(buf);j++)
            out<<buf[j];
    }

    return out;
}
istream &operator>>(istream &in,BigInteger &x)
{
    string s;
    if(!(in>>s))
        return in;
    x = s;
    return in;
}

int main()
{
    BigInteger a,b;
   cin>>a>>b;
   cout<<a<<endl;
   cout<<b<<endl;
    return 0;
}