BigInteger大整数类高精度

#include <cstdio>
#include <cstring>
#include <vector>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
using namespace std;

struct BigInteger {
static const int BASE = 100000000;
static const int WIDTH = 8;
vector<int> s;

BigInteger(long long num = 0) { *this = num; } // 鏋勯€犲嚱鏁?
BigInteger operator = (long long num) { // 璧嬪€艰繍绠楃
s.clear();
do {
s.push_back(num % BASE);
num /= BASE;
} while(num > 0);
return *this;
}
BigInteger operator = (const string& str) { // 璧嬪€艰繍绠楃
s.clear();
int x, len = (str.length() - 1) / WIDTH + 1;
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;
}
BigInteger operator + (const BigInteger& b) const {
BigInteger c;
c.s.clear();
for(int i = 0, g = 0; ; i++) {
if(g == 0 && i >= s.size() && i >= b.s.size()) break;
int x = g;
if(i < s.size()) x += s[i];
if(i < b.s.size()) x += b.s[i];
c.s.push_back(x % BASE);
g = x / BASE;
}
return c;
}
};

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;
}

#include <set>
#include <map>
set<BigInteger> s;
map<BigInteger, int> m;

int main() {
BigInteger y;
BigInteger x = y;
BigInteger z = 123;

BigInteger a, b;
cin >> a >> b;
cout << a + b << "\n";
cout << BigInteger::BASE << "\n";
system("pause");
return 0;
}