头文件 - intx.h
//intx.h
#ifndef INTX_H_
#define INTX_H_
#include <iostream>
#include <cstring>
#include <string>
class intx
{
private:
bool sign;
int *num;
int len;
static int process_char(const char *s,bool &sign,int *&num);
static bool unsign_gt(const int *a,const int lena,const int *b,const int lenb);
static bool unsign_gte(const int *a,const int lena,const int *b,const int lenb);
static int unsign_plus(const int *a,int lena,const int *b,int lenb,int *&result);
static int unsign_minus(const int *a,int lena,const int *b,int lenb,int *&result);
static int multiply_base(const int *a,const int lena,int n,int *&result);
static int unsgin_multiply(const int *a,const int lena,const int *b,const int lenb,int *&result);
static bool divide_gte(const int *a,int end,const int *b,int lenb);
static int unsign_divide(const int *a,const int lena,const int *b,const int lenb,int *&result);
static int unsign_mod(const int *a,const int lena,const int*b,const int lenb,int *&result);
public:
//constructor
intx();
intx(const char * s);
intx(const std::string & str);
intx(int n);
intx(const intx &b);
//destructor
~intx();
//calc
bool operator==(const intx &b) const;
bool operator>(const intx &b) const;
bool operator>=(const intx &b) const;
bool operator<(const intx &b) const;
bool operator<=(const intx &b) const;
intx operator-()const;
intx operator+(const intx &b) const;
intx operator-(const intx &b) const;
intx operator*(const intx &b) const;
intx operator/(const intx &b) const;
intx operator%(const intx &b) const;
//others
friend std::ostream& operator<<(std::ostream &os,const intx &a);
friend std::istream& operator>>(std::istream &is,intx &a);
int& operator[](const int sub) const;
intx& operator=(const intx &b);
intx& operator=(const char *s);
intx& operator=(const std::string &str);
int size(){return len;}
bool IsNatural()const{return sign;}
};
#endif
实现文件 - intx.cpp
//intx.cpp
#include "intx.h"
//private
int intx::process_char(const char *s,bool &sign,int *&num)
{
int len = strlen(s);
if(!len)//len == 0
{
sign = true;
num = new int[1];
num[0] = 0;
len = 1;
}
else
switch(s[0])
{
case '+':
sign = true;
--len;
num = new int[len];
for(int i = 0;i < len;++i)
num[i] = s[i + 1] - '0';
break;
case '-':
sign = false;
--len;
num = new int[len];
for(int i = 0;i < len;++i)
num[i] = s[i + 1] - '0';
break;
default:
sign = true;
num = new int[len];
for(int i = 0;i < len;++i)
num[i] = s[i] - '0';
break;
}
return len;
}
bool intx::unsign_gt(const int *a,const int lena,const int *b,const int lenb)
{
if(lena < lenb)
return false;
else if(lena > lenb)
return true;
else
{
for(int i = 0;i < lena;++i)
if(a[i] < b[i])
return false;
else if(a[i] > b[i])
return true;
return false;
}
}
bool intx::unsign_gte(const int *a,const int lena,const int *b,const int lenb)
{
if(lena < lenb)
return false;
else if(lena > lenb)
return true;
else
{
for(int i = 0;i < lena;++i)
if(a[i] < b[i])
return false;
else if(a[i] > b[i])
return true;
return true;
}
}
int intx::unsign_plus(const int *a,int lena,const int *b,int lenb,int *&result)
{
int rem;
if(lenb > lena)
{
const int *temp = a;
a = b;
b = temp;
rem = lena;
lena = lenb;
lenb = rem;
}
int len = lena + 1;
result = new int[len];
int sub = lena;
rem = 0;
--lena;
--lenb;
while(lenb >= 0)
{
rem += a[lena--] + b[lenb--];
result[sub--] = rem % 10;
rem /= 10;
}
while(lena >= 0)
{
rem += a[lena--];
result[sub--] = rem %10;
rem /= 10;
}
if(rem > 0)
{
result[sub] = rem;
}
else
{
--len;
int *p = new int[len];
memcpy(p,result + 1,sizeof(int)*len);
delete[] result;
result = p;
}
return len;
}
int intx::unsign_minus(const int *a,int lena,const int *b,int lenb,int *&result)//a must > b
{
int len = lena;
result = new int[len];
memcpy(result,a,sizeof(int)*len);//const int *a can't modify
--lenb;
--lena;
while(lenb >= 0)
{
if(a[lena] >= b[lenb])
result[lena] -= b[lenb];
else
{
result[lena] += 10 - b[lenb];
--result[lena -1];
}
--lena;
--lenb;
}
while(lena>=0)
{
if(result[lena] < 0)
{
result[lena] += 10;
--result[lena - 1];
--lena;
}
else
break;
}
int zero = 0;
while(zero < len)
if(result[zero] == 0)
++zero;
else
break;
if(zero == len)
{
delete[] result;
result = new int[1]{0};
len = 1;
}
else if(zero != 0)
{
len -= zero;
int *p = new int[len];
memcpy(p,result + zero,sizeof(int)*len);
delete[] result;
result = p;
}
return len;
}
bool intx::divide_gte(const int *a,const int end,const int *b,const int lenb)
{
int begin = 0;
while(a[begin] == 0)
{
++begin;
}
if(end - begin + 1 < lenb)
return false;
else if(end - begin + 1 > lenb)
return true;
else
{
for(int i = 0;i < lenb;++begin,++i)
if(a[begin] > b[i])
return true;
else if(a[begin] < b[i])
return false;
return true;
}
}
int intx::multiply_base(const int *a,int lena,const int n,int * &result)//the first may be 0
{
int len = lena + 1;
result = new int[len];
int rem = 0;
int sub = lena;
--lena;
while(lena >= 0)
{
rem += n * a[lena];
result[sub] = rem % 10;
rem /= 10;
--lena;
--sub;
}
if(rem > 0)
result[sub] = rem;
else
result[sub] = 0;
return len;
}
int intx::unsgin_multiply(const int *a,const int lena,const int *b,const int lenb,int *&result)//a on the top
{
int len = lena + lenb;
result = new int[len]{0};
int *MultiplyTemp;
int MultiplyBit = lenb - 1;//the subscript of number in the b to be multiplied
while(MultiplyBit >= 0)
{
int MultiplyTempSub = multiply_base(a,lena,b[MultiplyBit],MultiplyTemp);
//plus
int rem = 0;
int sub = len - (lenb - MultiplyBit);//the bit when result begin plus
--MultiplyTempSub;
while(MultiplyTempSub >= 0)
{
rem += result[sub] + MultiplyTemp[MultiplyTempSub];
result[sub] = rem % 10;
rem /= 10;
--sub;
--MultiplyTempSub;
}
if(rem > 0)
result[sub] += rem;
--MultiplyBit;
delete[] MultiplyTemp;
}
int zero = 0;
while(zero < len)
if(result[zero] == 0)
++zero;
else
break;
if(zero == len)
{
delete[] result;
result = new int[1]{0};
return 1;
}
else if(zero != 0)
{
len -= zero;
int *p = new int[len];
memcpy(p,result + zero,sizeof(int)*len);
delete[] result;
result = p;
}
return len;
}
int intx::unsign_divide(const int *a,const int lena,const int *b,const int lenb,int *&result)
{
if(lena < lenb)
{
result = new int[1]{0};
return 1;
}
//Judge the first bit
int CurrentBit = lenb - 1;//the current number on the consult
int len;
if(!divide_gte(a,CurrentBit,b,lenb))
if(CurrentBit + 1== lena)//lena == lenb && a < b
{
result = new int[1]{0};
return 1;
}
else
{
++CurrentBit;
len = lena - lenb;
result = new int[len];
}
else
{
len = lena - lenb + 1;
result = new int[len];
}
//copy
int *A = new int[lena];
memcpy(A,a,sizeof(int)*lena);
int sub = 0;//sub = CurrentBit - (lena - lenb)，too much calc
while(CurrentBit < lena)
{
result[sub] = 0;
do
{
//minus
int Asub = CurrentBit;
for(int i = lenb - 1;i >= 0;--Asub,--i)
if(A[Asub] >= b[i])
A[Asub] -= b[i];
else
{
A[Asub] += 10 - b[i];
--A[Asub - 1];
}
while(Asub >= 0)
if(A[Asub] < 0)
{
A[sub] += 10;
--A[Asub - 1];
--Asub;
}
else
break;
++result[sub];
}while(divide_gte(A,CurrentBit,b,lenb));
if(++sub,++CurrentBit == lena)
break;
while(!divide_gte(A,CurrentBit,b,lenb))
{
result[sub] = 0;
if(++sub,++CurrentBit == lena)
break;
}
}
delete[]A;
return len;
}
int intx::unsign_mod(const int *a,const int lena,const int *b,const int lenb,int *&result)
{
int len = lena;
result = new int[len];
memcpy(result,a,sizeof(int)*len);
if(lena < lenb)
return len;
//Judge the first bit
int CurrentBit = lenb - 1;//the current number on the consult
if(!divide_gte(result,CurrentBit,b,lenb))
{
if(CurrentBit + 1== len)//lena == lenb && a < b
return len;
else
++CurrentBit;
}
while(CurrentBit < len)
{
do
{
//minus
int sub = CurrentBit;
for(int i = lenb - 1;i >= 0;--sub,--i)
if(result[sub] >= b[i])
result[sub] -= b[i];
else
{
result[sub] += 10 - b[i];
--result[sub - 1];
}
while(sub >= 0)
if(result[sub] < 0)
{
result[sub] += 10;
--result[sub - 1];
--sub;
}
else
break;
}while(divide_gte(result,CurrentBit,b,lenb));
while(++CurrentBit != len)
if(divide_gte(result,CurrentBit,b,lenb))
break;
}
int zero = 0;
while(zero < len)
if(result[zero] == 0)
++zero;
else
break;
if(zero == len)
{
delete[] result;
result = new int[1]{0};
len = 1;
}
else if(zero != 0)
{
len -= zero;
int *p = new int[len];
memcpy(p,result + zero,sizeof(int)*len);
delete[] result;
result = p;
}
return len;
}
//constructor
intx::intx()
{
sign = true;
num = new int[1];
num[0] = 0;
len = 1;
}
intx::intx(const char *s)
{
len = process_char(s,sign,num);
}
intx::intx(const std::string &str)
{
const char *s = str.data();
new (this)intx(s);
}
intx::intx(int n)
{
if(n < 0)
sign = false;
else
sign = true;
if(n == 0)
{
len = 1;
num = new int[1]{0};
return;
}
len = 0;
int N = n;
while(n > 0)
{
n /= 10;
++len;
}
num = new int[len];
for(int i = len;i > 0;--i)
{
num[i - 1] = N % 10;
N /= 10;
}
}
intx::intx(const intx &b)
{
sign = b.sign;
len = b.len;
num = new int[len];
memcpy(num,b.num,sizeof(int) * len);
}
//destructor
intx::~intx()
{
delete[] num;
}
//calc
bool intx::operator==(const intx &b) const
{
if(len != b.len)
return false;
else if(sign != b.sign)
return false;
else
{
for(int i = 0;i < len;++i)
if(num[i] != b.num[i])
return false;
return true;
}
}
bool intx::operator>(const intx &b) const
{
if(sign)
if(b.sign)
return unsign_gt(num,len,b.num,b.len);
else
return true;
else
if(b.sign)
return false;
else
return !unsign_gt(num,len,b.num,b.len);
}
bool intx::operator>=(const intx &b)const
{
if(sign)
if(b.sign)
return unsign_gte(num,len,b.num,b.len);
else
return true;
else
if(b.sign)
return false;
else
return !unsign_gte(num,len,b.num,b.len);
}
bool intx::operator<(const intx &b) const
{
return !(*this >= b);
}
bool intx::operator<=(const intx &b) const
{
return !(*this > b);
}
intx intx::operator-()const
{
intx b = *this;
b.sign = !b.sign;
return b;
}
intx intx::operator+(const intx &b) const
{
intx sum;
delete[] sum.num;
if(sign)//a >= 0
if(b.sign)//a > 0 && b > 0
{
sum.sign = true;
sum.len = unsign_plus(num,len,b.num,b.len,sum.num);
}
else if(unsign_gte(num,len,b.num,b.len))// a > 0,b < 0,|a| >= |b|
{
sum.sign = true;
sum.len = unsign_minus(num,len,b.num,b.len,sum.num);
}
else// a > 0,b < 0,|a| < |b|
{
sum.sign = false;
sum.len = unsign_minus(b.num,b.len,num,len,sum.num);
}
else//a < 0
{
if(!b.sign)// a < 0, b < 0
{
sum.sign = false;
sum.len = unsign_plus(num,len,b.num,b.len,sum.num);
}
else if(unsign_gte(b.num,b.len,num,len))// a < 0,b > 0,|a| <= |b|
{
sum.sign = true;
sum.len = unsign_minus(b.num,b.len,num,len,sum.num);
}
else//a < 0 b > 0 , |a| > |b|
{
sum.sign = false;
sum.len = unsign_minus(num,len,b.num,b.len,sum.num);
}
}
return sum;
}
intx intx::operator-(const intx &b)const
{
return *this + (-b);
}
intx intx::operator*(const intx &b)const
{
intx product;
if(sign == b.sign)
product.sign = true;
else
product.sign = false;
delete[] product.num;
product.len = unsgin_multiply(num,len,b.num,b.len,product.num);
return product;
}
intx intx::operator/(const intx &b) const
{
intx consult;
if(sign == b.sign)
consult.sign = true;
else
consult.sign = false;
delete[] consult.num;
consult.len = unsign_divide(num,len,b.num,b.len,consult.num);
if(consult[0] == 0)//avoid "-0"
consult.sign = true;
return consult;
}
intx intx::operator%(const intx &b)const
{
intx modulo;
delete[] modulo.num;
modulo.sign = sign;
modulo.len = unsign_mod(num,len,b.num,b.len,modulo.num);
return modulo;
}
//others
std::ostream& operator<<(std::ostream &os,const intx &a)
{
if(!a.sign)
os << '-';
for(int i = 0;i < a.len;++i)
os << a.num[i];
return os;
}
std::istream& operator>>(std::istream &is,intx &a)
{
delete[] a.num;
int max = 16;
a.num = new int[max];
//Judge sign
char c;
a.len = 0;
c = getchar();
if(c == '-')
a.sign = false;
else if(c == '+')
a.sign = true;
else if(c <= '9' && c >= '1')//the first num
{
a.num[a.len] = c - '0';
++a.len;
}
else
{
a.sign = true;
a.num[a.len] = 0;
++a.len;
return is;
}
//makesure the first bit is inputed
if(a.len == 0)
{
c = getchar();
if(c >= '1' && c <= '9')
{
a.num[a.len] = c - '0';
++a.len;
}
else
{
a.sign = true;
a.num[a.len] = 0;
++a.len;
return is;
}
}
while(c = is.peek(),c >= '0' && c <= '9')
{
is >> c;
a.num[a.len] = c - '0';
if(++a.len == max)
{
max *= 2;
int *temp = new int[max];
memcpy(temp,a.num,sizeof(int)*a.len);
delete[] a.num;
a.num = temp;
}
}
return is;
}
int & intx::operator[](const int sub) const
{
return num[len - 1 - sub];
}
intx& intx::operator=(const intx &b)
{
if(this == &b)
return *this;
else
{
len = b.len;
sign = b.sign;
delete[] num;
num = new int[len];
memcpy(num,b.num,sizeof(int) * len);
return *this;
}
}
intx& intx::operator=(const char *s)
{
delete[] num;
len = process_char(s,sign,num);
return *this;
}
intx& intx::operator=(const std::string &str)
{
delete[] num;
len = process_char(str.data(),sign,num);
return *this;
}