纯C++简易数学库，实现大整数、浮点数、复数（待补充）

#include <cmath> #include <stack> #include "maths.h" /* 说明：本源码遵循BSD开源协议：使用、修改时，请不要修改命名空间 */ namespace ljs { char Integer::dec2hex(Integer c) const { if (c == 0 || c._data.size() == 0) { return '0'; } else if (c == 1) { return '1'; } else if (c == 2) { return '2'; } else if (c == 3) { return '3'; } else if (c == 4) { return '4'; } else if (c == 5) { return '5'; } else if (c == 6) { return '6'; } else if (c == 7) { return '7'; } else if (c == 8) { return '8'; } else if (c == 9) { return '9'; } else if (c == 10) { return 'a'; } else if (c == 11) { return 'b'; } else if (c == 12) { return 'c'; } else if (c == 13) { return 'd'; } else if (c == 14) { return 'e'; } else if (c == 15) { return 'f'; } return '0'; } Integer::Integer() { clear(); } Integer::Integer(long long num) { clear(); do { _data.push_back(num % _base); num = num / _base; } while (num > 0); } Integer::Integer(const std::string str) { clear(); if (str.length() == 0) { return; } if (str.at(0) == '-') { _sign = false; } int x; long long len = (str.length() - 1) / 8 + 1; for (int i = 0; i < len; i++) { long long end = str.length() - i * 8; long long start = max(0, end - 8); sscanf_s(str.substr(start, end - start).c_str(), "%d", &x); _data.push_back(x); } } Integer::~Integer() { clear(); } void Integer::clear() { _data.clear(); _sign = true; } size_t Integer::length() const { size_t x = 0; if (_data.size() > 0) { x += 8 * (_data.size() - 1); int y = _data.at(_data.size() - 1); for (; y > 0; ++x) y /= 10; } return x; } short Integer::bit(size_t i) const { return (int(_data.at(i / 8))) / (int(std::pow(10, i % 8))) % 10; } bool Integer::is_odd() const { return !is_even(); } bool Integer::is_even() const { return bit(0) % 2 == 0; } Integer Integer::hex_str(const std::string str) { clear(); std::string hexs = ""; long long n = str.length(); int s = 0; int d; Integer tp; while (--n > -1) { tp = "16"; tp = tp.power(n); if (str.at(s) <= '9' && str.at(s) >= '0') { d = str.at(s) - '0'; } else if (str.at(s) <= 'f' && str.at(s) >= 'a') { d = str.at(s) - 'a'; d += 10; } else if (str.at(s) <= 'F' && str.at(s) >= 'A') { d = str.at(s) - 'A'; d += 10; } s++; tp = tp * d; *this += tp; } return *this; } std::string Integer::hex_str() const { std::string hexs; hexs = ""; Integer tp = *this; while (tp > 0) { hexs = dec2hex(tp % 16) + hexs; tp = tp / 16; } return hexs; } Integer Integer::dec_str(const std::string str) { *this = str; return *this; } std::string Integer::dec_str() const { std::string res; res = ""; for (int i = 0; i < _data.size(); i++) { if (i == _data.size() - 1) { std::string sstemp = std::to_string(_data.at(i)); res = sstemp + res; } else { int n = _data.at(i); char temp[10]; memset(temp, 0, 10); sprintf_s(temp, 10, "%08d", n); res = temp + res; } } if (res == "") res = "0"; if (!_sign && res != "0") res = "-" + res; return res; } Integer Integer::operator=(long long num) { clear(); do { _data.push_back(num % _base); num = num / _base; } while (num > 0); return *this; } Integer Integer::operator=(const std::string str) { clear(); if (str.length() == 0) { return *this; } if (str.at(0) == '-') { _sign = false; } int x; long long len = (str.length() - 1) / 8 + 1; for (int i = 0; i < len; i++) { long long end = str.length() - i * 8; long long start = max(0, end - 8); sscanf_s(str.substr(start, end - start).c_str(), "%d", &x); _data.push_back(x); } return *this; } bool Integer::operator<(const Integer& num) const { if (!_sign && num._sign) { return true; } if (_sign && !num._sign) { return false; } if (!_sign && !num._sign) { Integer a = *this; a._sign = true; Integer b = num; b._sign = true; return b < a; } if (_data.size() != num._data.size()) return _data.size() < num._data.size(); for (long long i = _data.size() - 1; i >= 0; i--) if (_data.at(i) != num._data.at(i)) return _data.at(i) < num._data.at(i); return false; } bool Integer::operator>(const Integer& num)const { return num < *this; } bool Integer::operator<=(const Integer& num)const { return !(*this > num); } bool Integer::operator>=(const Integer& num)const { return !(*this < num); } bool Integer::operator!=(const Integer& num)const { return *this > num || *this < num; } bool Integer::operator==(const Integer& num)const { return !(num != *this); } Integer Integer::operator+(const Integer& num) const { if (_sign ^ num._sign) { Integer tmp = _sign ? num : *this; tmp._sign = true; return _sign ? *this - tmp : num - tmp; } Integer c; int g = 0; for (int i = 0;; i++) { if (g == 0 && i >= _data.size() && i >= num._data.size()) break; int x = g; if (i < _data.size()) { x += _data.at(i); } if (i < num._data.size()) { x += num._data.at(i); } c._data.push_back(x % _base); g = x / _base; } while (g > 0) { c._data.push_back(g % _base); g = g / _base; } c._sign = _sign; return c; } Integer Integer::operator++() { *this = *this + 1; return *this; } Integer Integer::operator+=(const Integer& num) { *this = *this + num; return *this; } Integer Integer::operator-(const Integer& num) const { Integer a = *this, b = num; if (!num._sign && !_sign) { b._sign = true; a._sign = true; return b - a; } if (!b._sign) { b._sign = true; return a + b; } if (!a._sign) { a._sign = true; b = a + b; b._sign = false; return b; } Integer c; if (a == b) { return c; } if (a < b) { c = (b - a); c._sign = false; return c; } int i; int h = 0; int x = 0; for (i = 0; i < b._data.size(); i++) { int m = a._data.at(i) - h; int n = b._data.at(i); if (m < n) { h = 1; m += _base; x += (m - n); } else { h = 0; x += (m - n); } c._data.push_back(x % _base); x = x / _base; } x -= h; for (; i < a._data.size(); i++) { x += a._data[i]; c._data.push_back(x % _base); x = x / _base; } while (x > 0) { c._data.push_back(x % _base); x = x / _base; } while (c._data.at(c._data.size() - 1) == 0) { c._data.pop_back(); } return c; } Integer Integer::operator--() { *this = *this - 1; return *this; } Integer Integer::operator-=(const Integer& num) { *this = *this - num; return *this; } Integer Integer::operator*(const Integer& num)const { Integer b; for (int i = 0; i < _data.size(); i++) { Integer c; long long g = 0; long long x = 0; for (int k = 0; k < i; k++) { c._data.push_back(0); } long long m = _data.at(i); for (int j = 0; j < num._data.size(); j++) { long long n = num._data.at(j); x = g + m * n; c._data.push_back(x % _base); g = x / _base; } while (g > 0) { c._data.push_back(g % _base); g = g / _base; } b += c; } b._sign = !(_sign ^ num._sign); return b; } Integer Integer::operator*=(const