紫书:
#include <iostream>
#include <string>
#include <cstring>
#include <cstdio>
using namespace std; const int maxn = 1000; struct bign{ int d[maxn], len; void clean() { while(len > 1 && !d[len-1]) len--; } bign() { memset(d, 0, sizeof(d)); len = 1; } bign(int num) { *this = num; } bign(char* num) { *this = num; } bign operator = (const char* num){ memset(d, 0, sizeof(d)); len = strlen(num); for(int i = 0; i < len; i++) d[i] = num[len-1-i] - '0'; clean(); return *this; } bign operator = (int num){ char s[20]; sprintf(s, "%d", num); *this = s; return *this; } bign operator + (const bign& b){ bign c = *this; int i; for (i = 0; i < b.len; i++){ c.d[i] += b.d[i]; if (c.d[i] > 9) c.d[i]%=10, c.d[i+1]++; } while (c.d[i] > 9) c.d[i++]%=10, c.d[i]++; c.len = max(len, b.len); if (c.d[i] && c.len <= i) c.len = i+1; return c; } bign operator - (const bign& b){ bign c = *this; int i; for (i = 0; i < b.len; i++){ c.d[i] -= b.d[i]; if (c.d[i] < 0) c.d[i]+=10, c.d[i+1]--; } while (c.d[i] < 0) c.d[i++]+=10, c.d[i]--; c.clean(); return c; } bign operator * (const bign& b)const{ int i, j; bign c; c.len = len + b.len; for(j = 0; j < b.len; j++) for(i = 0; i < len; i++) c.d[i+j] += d[i] * b.d[j]; for(i = 0; i < c.len-1; i++) c.d[i+1] += c.d[i]/10, c.d[i] %= 10; c.clean(); return c; } bign operator / (const bign& b){ int i, j; bign c = *this, a = 0; for (i = len - 1; i >= 0; i--) { a = a*10 + d[i]; for (j = 0; j < 10; j++) if (a < b*(j+1)) break; c.d[i] = j; a = a - b*j; } c.clean(); return c; } bign operator % (const bign& b){ int i, j; bign a = 0; for (i = len - 1; i >= 0; i--) { a = a*10 + d[i]; for (j = 0; j < 10; j++) if (a < b*(j+1)) break; a = a - b*j; } return a; } bign operator += (const bign& b){ *this = *this + b; return *this; } bool operator <(const bign& b) const{ if(len != b.len) return len < b.len; for(int i = len-1; i >= 0; i--) if(d[i] != b.d[i]) return d[i] < b.d[i]; return false; } bool operator >(const bign& b) const{return b < *this;} bool operator<=(const bign& b) const{return !(b < *this);} bool operator>=(const bign& b) const{return !(*this < b);} bool operator!=(const bign& b) const{return b < *this || *this < b;} bool operator==(const bign& b) const{return !(b < *this) && !(b > *this);} string str() const{ char s[maxn]={}; for(int i = 0; i < len; i++) s[len-1-i] = d[i]+'0'; return s; }
}; 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;
}
最全:
#include<string>
#include<iostream>
#include<iosfwd>
#include<cmath>
#include<cstring>
#include<stdlib.h>
#include<stdio.h>
#include<cstring>
using namespace std;const int MAX_L=2005; //最大长度,可以修改class bign
{
public:int len, s[MAX_L];//数的长度,记录数组
//构造函数bign();bign(const char*);bign(int);bool sign;//符号 1正数 0负数string toStr() const;//转化为字符串,主要是便于输出friend istream& operator>>(istream &,bign &);//重载输入流friend ostream& operator<<(ostream &,bign &);//重载输出流
//重载复制bign operator=(const char*);bign operator=(int);bign operator=(const string);
//重载各种比较bool operator>(const bign &) const;bool operator>=(const bign &) const;bool operator<(const bign &) const;bool operator<=(const bign &) const;bool operator==(const bign &) const;bool operator!=(const bign &) const;
//重载四则运算bign operator+(const bign &) const;bign operator++();bign operator++(int);bign operator+=(const bign&);bign operator-(const bign &) const;bign operator--();bign operator--(int);bign operator-=(const bign&);bign operator*(const bign &)const;bign operator*(const int num)const;bign operator*=(const bign&);bign operator/(const bign&)const;bign operator/=(const bign&);
//四则运算的衍生运算bign operator%(const bign&)const;//取模(余数)bign factorial()const;//阶乘bign Sqrt()const;//整数开根(向下取整)bign pow(const bign&)const;//次方
//一些乱乱的函数void clean();
};
#define max(a,b) a>b ? a : b
#define min(a,b) a<b ? a : bbign::bign()
{memset(s, 0, sizeof(s));len = 1;sign = 1;
}bign::bign(const char *num)
{*this = num;
}bign::bign(int num)
{*this = num;
}string bign::toStr() const
{string res;res = "";for (int i = 0; i < len; i++)res = (char)(s[i] + '0') + res;if (res == "")res = "0";if (!sign&&res != "0")res = "-" + res;return res;
}istream &operator>>(istream &in, bign &num)
{string str;in>>str;num=str;return in;
}ostream &operator<<(ostream &out, bign &num)
{out<<num.toStr();return out;
}bign bign::operator=(const char *num)
{memset(s, 0, sizeof(s));char a[MAX_L] = "";if (num[0] != '-')strcpy(a, num);elsefor (int i = 1; i < strlen(num); i++)a[i - 1] = num[i];sign = !(num[0] == '-');len = strlen(a);for (int i = 0; i < strlen(a); i++)s[i] = a[len - i - 1] - 48;return *this;
}bign bign::operator=(int num)
{char temp[MAX_L];sprintf(temp, "%d", num);*this = temp;return *this;
}bign bign::operator=(const string num)
{const char *tmp;tmp = num.c_str();*this = tmp;return *this;
}bool bign::operator<(const bign &num) const
{if (sign^num.sign)return num.sign;if (len != num.len)return len < num.len;for (int i = len - 1; i >= 0; i--)if (s[i] != num.s[i])return sign ? (s[i] < num.s[i]) : (!(s[i] < num.s[i]));return !sign;
}bool bign::operator>(const bign&num)const
{return num < *this;
}bool bign::operator<=(const bign&num)const
{return !(*this>num);
}bool bign::operator>=(const bign&num)const
{return !(*this<num);
}bool bign::operator!=(const bign&num)const
{return *this > num || *this < num;
}bool bign::operator==(const bign&num)const
{return !(num != *this);
}bign bign::operator+(const bign &num) const
{if (sign^num.sign){bign tmp = sign ? num : *this;tmp.sign = 1;return sign ? *this - tmp : num - tmp;}bign result;result.len = 0;int temp = 0;for (int i = 0; temp || i < (max(len, num.len)); i++){int t = s[i] + num.s[i] + temp;result.s[result.len++] = t % 10;temp = t / 10;}result.sign = sign;return result;
}bign bign::operator++()
{*this = *this + 1;return *this;
}bign bign::operator++(int)
{bign old = *this;++(*this);return old;
}bign bign::operator+=(const bign &num)
{*this = *this + num;return *this;
}bign bign::operator-(const bign &num) const
{bign b=num,a=*this;if (!num.sign && !sign){b.sign=1;a.sign=1;return b-a;}if (!b.sign){b.sign=1;return a+b;}if (!a.sign){a.sign=1;b=bign(0)-(a+b);return b;}if (a<b){bign c=(b-a);c.sign=false;return c;}bign result;result.len = 0;for (int i = 0, g = 0; i < a.len; i++){int x = a.s[i] - g;if (i < b.len) x -= b.s[i];if (x >= 0) g = 0;else{g = 1;x += 10;}result.s[result.len++] = x;}result.clean();return result;
}bign bign::operator * (const bign &num)const
{bign result;result.len = len + num.len;for (int i = 0; i < len; i++)for (int j = 0; j < num.len; j++)result.s[i + j] += s[i] * num.s[j];for (int i = 0; i < result.len; i++){result.s[i + 1] += result.s[i] / 10;result.s[i] %= 10;}result.clean();result.sign = !(sign^num.sign);return result;
}bign bign::operator*(const int num)const
{bign x = num;bign z = *this;return x*z;
}
bign bign::operator*=(const bign&num)
{*this = *this * num;return *this;
}bign bign::operator /(const bign&num)const
{bign ans;ans.len = len - num.len + 1;if (ans.len < 0){ans.len = 1;return ans;}bign divisor = *this, divid = num;divisor.sign = divid.sign = 1;int k = ans.len - 1;int j = len - 1;while (k >= 0){while (divisor.s[j] == 0) j--;if (k > j) k = j;char z[MAX_L];memset(z, 0, sizeof(z));for (int i = j; i >= k; i--)z[j - i] = divisor.s[i] + '0';bign dividend = z;if (dividend < divid) { k--; continue; }int key = 0;while (divid*key <= dividend) key++;key--;ans.s[k] = key;bign temp = divid*key;for (int i = 0; i < k; i++)temp = temp * 10;divisor = divisor - temp;k--;}ans.clean();ans.sign = !(sign^num.sign);return ans;
}bign bign::operator/=(const bign&num)
{*this = *this / num;return *this;
}bign bign::operator%(const bign& num)const
{bign a = *this, b = num;a.sign = b.sign = 1;bign result, temp = a / b*b;result = a - temp;result.sign = sign;return result;
}bign bign::pow(const bign& num)const
{bign result = 1;for (bign i = 0; i < num; i++)result = result*(*this);return result;
}bign bign::factorial()const
{bign result = 1;for (bign i = 1; i <= *this; i++)result *= i;return result;
}void bign::clean()
{if (len == 0) len++;while (len > 1 && s[len - 1] == '\0')len--;
}bign bign::Sqrt()const
{if(*this<0)return -1;if(*this<=1)return *this;bign l=0,r=*this,mid;while(r-l>1){mid=(l+r)/2;if(mid*mid>*this)r=mid;elsel=mid;}return l;
}bign num0,num1,res;int main() {num0 = 1, num1 = 2;res=num0-num1;cout << res << endl;return 0;
}
出处:
紫书和
https://www.cnblogs.com/HarryGuo2012/p/4524041.html