大整数类 模板
自己写的大整数模板，已经升级到V2.0
功能：
计算大整数加减乘数取模运算，支持无限位数，支持正负数输入输出及运算，支持判断两个大整数的大小
保障：
1.VC++2013，GCC4.7.3运行测试通过
2.学校OJ加减乘除取模均AC
//BigInt V2.0
//By KunSoft
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>
#include <deque>
#include <iterator>
#include <algorithm>
using namespace std;
typedef long long LLT;
class BigInt
{
public:
BigInt() :negative(false) {}
BigInt(const LLT);
BigInt(const char*);
BigInt(const string);
BigInt(const BigInt & x);
BigInt & operator = (const BigInt &);
friend istream & operator >> (istream &, BigInt &);
friend ostream & operator << (ostream &, BigInt);
BigInt operator + (const BigInt &) const;
BigInt operator - (const BigInt &) const;
BigInt operator * (const BigInt &) const;
BigInt operator / (const LLT &) const;
LLT operator % (const LLT &) const;
bool operator > (const BigInt &) const;
bool operator == (const BigInt &) const;
bool operator >= (const BigInt &) const;
friend BigInt abs(const BigInt &);
BigInt operator - () const;
private:
deque<int> num;
bool negative;
};
BigInt::BigInt(const LLT x){
LLT t = abs(x);
negative = x >= 0 ? true : false;
while (t > 0){
num.push_back(t % 10);
t = t / 10;
}
}
BigInt::BigInt(const char* str){
unsigned i = str[0] == '-' ? 1 : 0;
this->negative = str[0] == '-' ? true : false;
for (; i < strlen(str); ++i) num.push_back(str[i] - '0');
}
BigInt::BigInt(const string str){
unsigned i = str[0] == '-' ? 1 : 0;
this->negative = str[0] == '-' ? true : false;
for (; i < str.size(); ++i) num.push_back(str[i] - '0');
}
BigInt::BigInt(const BigInt &x){
negative = x.negative;
num = x.num;
}
BigInt & BigInt::operator = (const BigInt &x){
negative = x.negative;
num = x.num;
return (*this);
}
istream & operator >> (istream &is, BigInt & x){
string str; is >> str;
x = str;
return is;
}
ostream & operator << (ostream &os, BigInt x){
if (x.negative) os << '-';
for (unsigned i = 0; i != x.num.size(); ++i)
os << x.num[i];
return os;
}
bool BigInt::operator > (const BigInt & rhs) const {
BigInt x = (*this), y = rhs;
if (!x.negative && y.negative) return true;
if (x.negative && !y.negative) return false;
if (x.negative && y.negative) swap(x, y);
if (x.num.size() > y.num.size()) return true;
if (x.num.size() < y.num.size()) return false;
for (unsigned i = 0; i != x.num.size(); ++i) {
if (x.num[i] > y.num[i]) return true;
if (x.num[i] < y.num[i]) return false;
}
return false;
}
bool BigInt::operator == (const BigInt & rhs) const {
return negative == rhs.negative && num == rhs.num;
}
bool BigInt::operator >= (const BigInt & rhs) const {
return *this > rhs || *this == rhs;
}
BigInt abs(const BigInt & rhs){
BigInt res;
res.negative = false;
res.num = rhs.num;
return res;
}
BigInt BigInt::operator - () const {
BigInt ret = *this; ret.negative = !ret.negative;
return ret;
}
BigInt BigInt::operator + (const BigInt & y) const {
if (!this->negative && y.negative) return *this - abs(y);
if (this->negative && !y.negative) return y - abs(*this);
if (this->negative && y.negative) return -(abs(*this) + abs(y));
BigInt x = *this, res;
int temp = 0;
for (int i = x.num.size() - 1, j = y.num.size() - 1; i >= 0 || j >= 0; --i, --j) {
int a = i < 0 ? 0 : x.num[i];
int b = j < 0 ? 0 : y.num[j];
res.num.push_front((a + b + temp) % 10);
temp = (a + b + temp) / 10;
}
if (temp != 0) res.num.push_front(temp);
return res;
}
BigInt BigInt::operator * (const BigInt & y) const {
deque<int> a, b, res;
copy(this->num.begin(), this->num.end(), front_inserter(a));
copy(y.num.begin(), y.num.end(), front_inserter(b));
res.resize(a.size() + b.size() + 5);
for (unsigned i = 0; i < a.size(); ++i) for (unsigned j = 0; j < b.size(); ++j)
res[i + j] += a[i] * b[j];
for (unsigned i = 0; i < res.size() - 1; ++i){
res[i + 1] += res[i] / 10;
res[i] %= 10;
}
while (res.size() >= 2 && res.back() == 0)
res.pop_back();
reverse(res.begin(), res.end());
BigInt ret; ret.negative = this->negative ^ y.negative; ret.num = res;
return ret;
}
BigInt BigInt::operator - (const BigInt & y) const {
if (!this->negative && y.negative) return *this + abs(y);
if (this->negative && !y.negative) return -(abs(*this) + y);
if (this->negative && y.negative) return abs(y) - abs(*this);
deque<int> a, b, res; BigInt ret;
copy(this->num.begin(), this->num.end(), front_inserter(a));
copy(y.num.begin(), y.num.end(), front_inserter(b));
if (y > *this) swap(a, b), ret.negative = true;
res.resize(max(a.size(), b.size()) + 5);
for (unsigned i = 0, j = 0; i < a.size() || j < b.size(); ++i, ++j){
int m = i < a.size() ? a[i] : 0;
int n = j < b.size() ? b[j] : 0;
res[i] = m - n;
}
for (unsigned i = 0; i < res.size() - 1; ++i) if (res[i] < 0) {
res[i] += 10;
--res[i + 1];
}
while (res.size() >= 2 && res.back() == 0)
res.pop_back();
reverse(res.begin(), res.end()); ret.num = res;
return ret;
}
BigInt BigInt::operator / (const LLT & y) const {
LLT temp = 0;
BigInt x = (*this), res;
for (unsigned i = 0; i < x.num.size(); ++i){
temp = temp * 10 + x.num[i];
res.num.push_back((int)(temp / y));
temp %= y;
}
while (res.num.size() >= 2 && res.num.front() == 0)
res.num.pop_front();
return res;
}
LLT BigInt::operator % (const LLT & y) const {
LLT res = 0;
for (unsigned i = 0; i < this->num.size(); ++i)
res = (res * 10 + this->num[i]) % y;
return res;
}
int main()
{
BigInt a, b;
while (cin >> a >> b)
cout << a + b << endl;
return 0;
}
下面是老版的V1.0版本提供参考，使用数组实现，速度会快一些。
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>
#include <algorithm>
#define MAXN 1024
using namespace std;
class BigInt
{
private:
int num[MAXN];
int len;
int flag;
public:
BigInt()
{
memset(num, 0, sizeof(num));
len = 0;
flag = 1;
};
BigInt(const int);
BigInt(const char*);
BigInt(const string);
BigInt(const BigInt &x);
BigInt &operator = (const BigInt &);
friend istream &operator >> (istream &, BigInt &);
friend ostream &operator << (ostream &, BigInt &);
BigInt operator + (const BigInt &);
BigInt operator - (const BigInt &);
BigInt operator * (const BigInt &);
BigInt operator / (const long long int &);
long long int operator % (const long long int &);
bool operator > (const BigInt &);
friend BigInt rev(const BigInt &x);
};
//将一个int类型的变量转化为BigInt类型
BigInt::BigInt(const int x)
{
memset(num, 0, sizeof(num));
len = 0;
int t;
if(x < 0)
{
t = -x;
flag = -1;
}
else
t = x;
while (t > 0)
{
num[len++] = t % 10;
t = t / 10;
}
}
//将一个C风格字符串的变量转化为BigInt类型
BigInt::BigInt(const char* str)
{
memset(num, 0, sizeof(num));
len = strlen(str);
for (int i = 0; i < len; i++)
{
num[i] = str[i] - '0';
}
}
//将一个string字符串的变量转化为BigInt类型
BigInt::BigInt(const string str)
{
string temp(str);
memset(num, 0, sizeof(num));
len = temp.size();
int cnt = 0;
for (string::iterator i = temp.begin(); i != temp.end(); i++)
num[cnt++] = *i - '0';
}
//拷贝BigInt对象
BigInt::BigInt(const BigInt &x)
{
len = x.len;
flag = x.flag;
memset(num, 0, sizeof(num));
for (int i = 0; i < len; i++)
num[i] = x.num[i];
}
//重载赋值运算符
BigInt & BigInt::operator = (const BigInt &x)
{
len = x.len;
flag = x.flag;
memset(num, 0, sizeof(num));
for (int i = 0; i < len; i++)
num[i] = x.num[i];
return (*this);
}
//重载输入运算符
istream &operator >> (istream &is, BigInt &x)
{
string temp;
is >> temp;
memset(x.num, 0, sizeof(x.num));
x.len = temp.size();
int cnt = 0;
for (string::iterator i = temp.begin(); i != temp.end(); i++)
x.num[cnt++] = *i - '0';
return is;
}
//重载输出运算符
ostream &operator << (ostream &os, BigInt &x)
{
if(x.flag == -1)
printf("-");
for (int i = 0; i < x.len; i++)
printf("%d", x.num[i]);
return os;
}
//获取翻转BigInt后的BigInt
BigInt rev(const BigInt &x)
{
BigInt res;
res.len = x.len;
res.flag = x.flag;
memset(res.num, 0, sizeof(res.num));
for(int i=0; i<res.len; i++)
res.num[res.len-1-i] = x.num[i];
return res;
}
//判断两个BigInt的大小
bool BigInt::operator > (const BigInt &y)
{
BigInt x = (*this);
if(x.len > y.len)
return true;
else if(x.len < y.len)
return false;
else if(x.len == y.len)
{
for(int i=0; i<x.len; i++)
{
if(x.num[i] > y.num[i])
return true;
else if(x.num[i] < y.num[i])
return false;
}
return false;
}
}
//两个BigInt之间的加法运算
BigInt BigInt::operator + (const BigInt &y)
{
BigInt x(*this);
BigInt res;
int i, j;
int cnt = 0, temp = 0;
for (i = x.len - 1, j = y.len - 1; i >= 0 || j >= 0; i--, j--)
{
int a = i < 0 ? 0 : x.num[i];
int b = j < 0 ? 0 : y.num[j];
res.num[cnt++] = (a + b + temp) % 10;
temp = (a + b + temp) / 10;
}
if (temp != 0)
res.num[cnt++] = temp;
res.len = cnt;
for (int i = 0; i < (res.len / 2); i++)
{
int t = res.num[i];
res.num[i] = res.num[res.len - 1 - i];
res.num[res.len - 1 - i] = t;
}
return res;
}
//两个BigInt之间的乘法运算
BigInt BigInt::operator * (const BigInt &y)
{
BigInt a, b, res;
BigInt ret;
a = rev(*this);
b = rev(y);
for(int i=0; i<a.len; i++)
for(int j=0; j<b.len; j++)
res.num[i+j] += a.num[i] * b.num[j];
for(int i=0; i<MAXN-1; i++)
{
res.num[i+1] += res.num[i]/10;
res.num[i] = res.num[i]%10;
}
for(int i = MAXN-1; i>=0; --i)
{
if(res.num[i]!=0)
{
res.len = i + 1;
break;
}
}
if(res.len==0)
{
res.len = 1;
res.num[0] = 0;
}
ret = rev(res);
return ret;
}
//两个BigInt之间的减法运算
BigInt BigInt::operator - (const BigInt &y)
{
BigInt a = rev(*this), b = rev(y);
BigInt res, ret;
if(b > a)
{
swap(a, b);
res.flag = -1;
}
for(int i=0, j=0; i<a.len || j<b.len; i++, j++)
{
int m = i<a.len ? a.num[i] : 0;
int n = j<b.len ? b.num[j] : 0;
res.num[i] = m - n;
}
for(int i=0; i<MAXN-1; i++)
{
if(res.num[i]<0)
{
res.num[i] += 10;
res.num[i+1]--;
}
}
for(int i = MAXN-1; i>=0; --i)
{
if(res.num[i]!=0)
{
res.len = i + 1;
break;
}
}
if(res.len==0)
{
res.len = 1;
res.num[0] = 0;
}
ret = rev(res);
return ret;
}
//BigInt除以一个长整形运算
BigInt BigInt::operator / (const long long int &y)
{
long long int temp = 0;
BigInt x = (*this);
BigInt res;
for(int i=0; i<len; i++)
{
temp = temp*10 + x.num[i];
res.num[i] = temp / y;
temp = temp % y;
}
//去前导0
int cnt = 0;
for(int i = 0; i<MAXN; ++i)
{
if(res.num[i]!=0)
{
cnt = i;
break;
}
}
for(int i = cnt; i<MAXN; ++i)
{
int t = res.num[i];
res.num[i] = res.num[i-cnt];
res.num[i-cnt] = t;
}
res.len = x.len - cnt;
return res;
}
//BigInt对一个长整形做取余运算
long long int BigInt::operator % (const long long int &y)
{
long long int temp = 0;
BigInt x = (*this);
BigInt res;
for(int i=0; i<len; i++)
{
temp = temp*10 + x.num[i];
res.num[i] = temp / y;
temp = temp % y;
}
return temp;
}
int main()
{
return 0;
}
