{var%20f='http://v.t.sina.com.cn/share/share.php?appkey=1515056452',u=z||d.location,p=['&url=',e(u),'&title=',e(t||d.title),'&source=',e(r),'&sourceUrl=',e(l),'&content=',c||'gb2312','&pic=',e(p||'')].join('');function%20a(){if(!window.open([f,p].join(''),'mb',['toolbar=0,status=0,resizable=1,width=440,height=430,left=',(s.width-440)/2,',top=',(s.height-430)/2].join('')))u.href=[f,p].join('');};if(/Firefox/.test(navigator.userAgent))setTimeout(a,0);else%20a();})(screen,document,encodeURIComponent,'','','https://www.xiaopingtou.cn//data/attach/topic/topicKPo7gB.jpg', '推荐 liyushaohua 的文章《大整数加减乘除及取模运算 C++实现》','https://www.xiaopingtou.net/article-55176.html','页面编码gb2312|utf-8默认gb2312'));){kind=link}
最近事情实在是太多了，一直没有时间写博客，昨天刚刚忙完硕士开题，虽然还是有很多的事情要做，
但实在是不想弄了。想起一个月之前就已经写完的一个大整数加减乘除法的程序，今天把它贴出来和大家分享，
目前我只是做了简单的测试，可能程序中还存在不好的bug，也希望大家能一块帮着指出其中的错误！！
希望和大家一块学习共勉 .....
工程下载地址（也可以留下邮箱，我会将工程发过去）：http://download.csdn.net/detail/doufei_ccst/6693721
首先是实现大整数的头文件：BitInt.h
BitInt.cpp
测试主函数：main.cpp
测试数据放在一个data.txt文件中，内容是两个操作数，如下：
程序的运行结果是：
工程下载地址（也可以留下邮箱，我会将工程发过去）：http://download.csdn.net/detail/doufei_ccst/6693721 希望能够指正程序中的错误和不足，共同学习进步 ....
首先是实现大整数的头文件：BitInt.h
#ifndef DOUFEI_BIGINT_HEADER
#define DOUFEI_BIGINT_HEADER
#include
#include
class CBigInt
{
public:
explicit CBigInt() ;
CBigInt(const int i) ;
CBigInt(const std :: string& strValues) ;
CBigInt(const CBigInt& bigInt) ; //复制构造函数
~CBigInt() ;
public:
bool inline isPositive() {return flag ; };
int compareBitInt(const CBigInt& rhs)const ; //比较两个数的大小
CBigInt& operator = (const CBigInt& rhs) ; //赋值操作符重载
friend std :: ostream& operator << (std :: ostream& ou, const CBigInt& bigInt) ; //重载输出操作符
friend std :: istream& operator >> (std :: istream& in, CBigInt& bigInt) ; //输入操作符的重载
friend const CBigInt operator + (const CBigInt& lhs, const CBigInt& rhs ) ; //加法操作重载
friend const CBigInt operator - (const CBigInt& lhs, const CBigInt& rhs) ; //减法操作符重载
friend const CBigInt operator * (const CBigInt& lhs, const CBigInt& rhs) ; //乘法操作符重载
friend const CBigInt operator / (const CBigInt& lhs, const CBigInt& rhs) ; //除法操作重载
friend const CBigInt operator % (const CBigInt& lhs, const CBigInt& rhs) ; //取模运算操作符重载
void setValue(const std :: string& strValues) ; //根据字符串设置数值
const CBigInt absolute()const ; //绝对值
private:
std :: string values ; //保存所有位上的数字
bool flag ; //true表示正数，false表示负数，0默认为正数
};
std :: ostream& operator << (std :: ostream& ou, const CBigInt& bigInt) ;
std :: istream& operator >> (std :: istream& in, CBigInt& bigInt) ;
const CBigInt operator + (const CBigInt& lhs, const CBigInt& rhs ) ; //加法操作符重载
const CBigInt operator - (const CBigInt& lhs, const CBigInt& rhs) ; //剑法操作符重载
const CBigInt operator * (const CBigInt& lhs, const CBigInt& rhs) ; //乘法操作符重载
const CBigInt operator / (const CBigInt& lhs, const CBigInt& rhs) ; //除法操作重载
const CBigInt operator % (const CBigInt& lhs, const CBigInt& rhs) ; //取模运算操作符重载
#endif
BitInt.cpp
#include "BigInt.h"
#include
#include
#include
#include
#include
#include
using namespace std;
CBigInt :: CBigInt() : values(""), flag(true)
{
}
CBigInt :: CBigInt(const int i)
{
values.clear() ;
if (i >= 0) flag = true ;
else
flag = false ;
int v = abs(i) ;
while(v)
{
values.push_back(char('0' + (v % 10))) ;
v /= 10 ;
}
reverse(values.begin(), values.end()) ;
if (values.empty())
{
values.push_back('0') ;
flag = true ;
}
}
CBigInt :: CBigInt(const string& strValues)
{
setValue(strValues) ; //调用成员函数完成
}
CBigInt :: CBigInt(const CBigInt& bigInt) : values(bigInt.values), flag(bigInt.flag)
{
}
CBigInt :: ~CBigInt()
{}
const CBigInt CBigInt :: absolute() const
{
CBigInt ret(*this) ;
ret.flag = true ;
return ret ;
}
int CBigInt :: compareBitInt(const CBigInt& rhs)const
{
//异号情况
if (flag && !rhs.flag) return 1 ;
if (!flag && rhs.flag) return -1 ;
//同号情况，先比较绝对值，然后根据符号判断大小
int ret = 0 ;
if (values.length() > rhs.values.length()) ret = 1 ;
else
if (values.length() < rhs.values.length()) ret = -1 ;
else
ret = values.compare(rhs.values) ;
if (flag) return ret ;
return -ret ;
}
void CBigInt :: setValue(const string& strValues)
{
values.clear() ;
string tmpStr(strValues.begin() + strValues.find_first_not_of(' '), strValues.end()) ; //去掉前面的空格
if (tmpStr.empty())
{
values.push_back('0') ;
flag = true ;
return ;
}
if (tmpStr.at(0) == '-' )
flag = false ;
else
flag = true ;
int i = tmpStr.find_first_of("0123456789") ;
int j = tmpStr.find_last_of("0123456789") ;
values = tmpStr.substr(i, j - i + 1) ;//从符号位之后开始的所有数字，直到遇到第一个非数字位
}
CBigInt& CBigInt :: operator = (const CBigInt& rhs)
{
this->values = rhs.values ;
this->flag = rhs.flag ;
return *this ;
}
ostream& operator << (ostream& ou, const CBigInt& bigInt)
{
if (!bigInt.flag)
ou << '-';
ou << bigInt.values ;
return ou ;
}
istream& operator >> (istream& in, CBigInt& bigInt)
{
string str ;
in >> str ;
bigInt.setValue(str) ; //设置读入的新的数值
return in ;
}
const CBigInt operator + (const CBigInt& lhs, const CBigInt& rhs)
{
CBigInt ret ;
if (lhs.flag == rhs.flag) //符号相同
{
string lvalues(lhs.values) , rvalues(rhs.values) ;
reverse(lvalues.begin(), lvalues.end()) ;
reverse(rvalues.begin(), rvalues.end()) ;
//逐位相加
int i = 0;
for ( ; i < lvalues.length() && i < rvalues.length(); ++ i)
ret.values.push_back(lvalues.at(i) + rvalues.at(i) - '0') ;
if (i < lvalues.length())
for (; i < lvalues.length(); ++ i)
ret.values.push_back(lvalues.at(i)) ;
else
for (; i < rvalues.length(); ++ i)
ret.values.push_back(rvalues.at(i)) ;
//处理进位
int carry = 0;
for (int i = 0; i < ret.values.length(); ++ i)
{
int newValue = ret.values.at(i) - '0' + carry ;
carry = newValue/ 10 ;
ret.values.at(i) = newValue - carry * 10 + '0' ;
}
if (carry)
ret.values.push_back(carry + '0') ;
//处理符号
ret.flag = lhs.flag ;
}
else //符号不同
{
CBigInt absL = lhs.absolute() ;
CBigInt absR = rhs.absolute() ;
int compFlag = absL.compareBitInt(absR) ;
if (compFlag == 0)
{
ret.setValue("0") ;
ret.flag = true ;
return ret ;
}
else
{
if (compFlag == -1) //交换位置，使得absL > absR
{
CBigInt tmp(absL) ;
absL = absR ;
absR = tmp ;
}
reverse(absL.values.begin(), absL.values.end()) ;
reverse(absR.values.begin(), absR.values.end()) ;
//处理差值
int i = 0;
for (; i < absL.values.length() && i < absR.values.length(); ++ i)
ret.values.push_back(absL.values.at(i) - absR.values.at(i) + '0') ;
if (i < absL.values.length()) //不可能出现i < absR.values.length()的情况
for (; i < absL.values.length(); ++ i)
ret.values.push_back(absL.values.at(i)) ;
//处理借位
int carry = 0 ;
for (i = 0; i < ret.values.length(); ++ i)
{
int newValue = ret.values.at(i) - carry - '0' ;
if (newValue < 0) carry = 1 ; //向前借位
else carry = 0 ;
ret.values.at(i) = newValue + carry * 10 + '0' ;
}
//处理符号
if (compFlag == 1)
ret.flag = lhs.flag ;
else
ret.flag = rhs.flag;
}
}
reverse(ret.values.begin(), ret.values.end()) ;
int i = ret.values.find_first_not_of(" 0") ;
if (i == string :: npos)//空的，说明结果是0
{
ret.setValue("0") ;
ret.flag = true ;
return ret ;
}
ret.values = string(ret.values.begin() + ret.values.find_first_not_of(" 0"), ret.values.end()) ; //去掉前面的空白和0
return ret ;
}
const CBigInt operator - (const CBigInt& lhs, const CBigInt& rhs)
{
CBigInt tmpRhs(rhs) ;
tmpRhs.flag = !tmpRhs.flag ; //取负号
return (lhs + tmpRhs) ;
}
//乘法操作符重载
const CBigInt operator * (const CBigInt& lhs, const CBigInt& rhs)
{
CBigInt ret ;
int flag1 = lhs.compareBitInt(CBigInt(0)) ;
int flag2 = rhs.compareBitInt(CBigInt(0)) ;
if (flag1 == 0 || flag2 == 0)
{
ret.setValue("0") ;
ret.flag = true ;
return ret ;
}
if (lhs.flag == rhs.flag)
ret.flag = true ;//同号为正，异号为负
else
ret.flag = false ;
string lvalues(lhs.values), rvalues(rhs.values) ;
reverse(lvalues.begin(), lvalues.end()) ;
reverse(rvalues.begin(), rvalues.end()) ;
ret.values.resize(lvalues.size() + rvalues.size(), '0') ;
//相乘
for (int i = 0; i < lvalues.size(); ++ i)
for (int j = 0; j < rvalues.size(); ++ j)
{
int newValue = ret.values[i + j] + (lvalues[i] - '0') * (rvalues[j] - '0') - '0';
int carry = newValue / 10 ;
ret.values[i + j] = newValue % 10 + '0' ;
//这里之所以对每一位进行进位处理，是为了防止出现溢出情况的出现，如'0' + 9 * 9 = 48 + 81 > 127已经溢出
for (int k = i + j + 1; carry != 0 && k < ret.values.size(); ++ k) //处理进位
{
ret.values[ k - 1 ] = newValue % 10 + '0' ;
newValue = ret.values[k] + carry - '0';
ret.values[k] = newValue % 10 + '0' ;
carry = newValue / 10 ;
}
}
reverse(ret.values.begin(), ret.values.end()) ; //翻转
ret.values = string(ret.values.begin() + ret.values.find_first_not_of(" 0"), ret.values.end()) ; //去掉前面的空白和0
return ret ;
}
const CBigInt operator / (const CBigInt& lhs, const CBigInt& rhs) //除法操作重载
{
CBigInt ret ;
assert(rhs.compareBitInt(CBigInt(0)) != 0) ;
ret.setValue("0") ; //初始化为0
CBigInt absL(lhs.absolute()) ;
CBigInt absR(rhs.absolute()) ;
int comFlag = absL.compareBitInt(absR) ;
if (comFlag < 0)
return ret ;
if(comFlag == 0)
{
ret.setValue("1") ;
if (lhs.flag == rhs.flag) ret.flag = true ;
else
ret.flag = false ;
return ret ;
}
int movCount = absL.values.size() - absR.values.size() ;
const CBigInt tenBigInt(10) ;
//使用减法实现除法的操作
do
{
CBigInt tmp(absR) ;
for (int i = 0; i < movCount; ++ i) //tmp是10的movCount次方
tmp = tmp * tenBigInt ;
int addNum = 0 ;
while(absL.compareBitInt(tmp) >= 0)
{
absL = absL - tmp ;
addNum ++ ;
}
ret = ret * tenBigInt + CBigInt (addNum) ;
movCount -- ;
}while (movCount >= 0);
if (lhs.flag == rhs.flag) ret.flag = true ;
else
ret.flag = false ;
return ret ;
}
const CBigInt operator % (const CBigInt& lhs, const CBigInt& rhs) //取模运算操作符重载
{
CBigInt divTmp = lhs / rhs ;
return (lhs - rhs * divTmp) ;
} 测试主函数：main.cpp
#include
#include
#include "BigInt.h"
#include
using namespace std ;
int main(int argc, char** argv)
{
ifstream in("data.txt") ;
#define cin in
string num1, num2 ;
cin >> num1 >> num2 ;
CBigInt bi1(num1);
CBigInt bi2(num2) ;
cout << "第一个操作数是：" << bi1 << endl ;
cout << "第二个操作数是：" << bi2 << endl;
cout << "乘法结果:" << bi1 * bi2 << endl;
cout <<"加法结果：" << (bi1 + bi2) << endl;
cout << "减法结果：" <<(bi1 - bi2) << endl;
cout << "除法的结果是：" << bi1/bi2 << endl;
cout << "取模的结果是：" << bi1 % bi2 << endl;
return 0 ;
}
测试数据放在一个data.txt文件中，内容是两个操作数，如下：
999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
-999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998999899989998
程序的运行结果是：
工程下载地址（也可以留下邮箱，我会将工程发过去）：http://download.csdn.net/detail/doufei_ccst/6693721 希望能够指正程序中的错误和不足，共同学习进步 ....