WAY?
为什么会有大数据运算？缘由？
在c++中常用的数据类型有 char:1 bit,short 2 bit，int 4 bit，long long 8 bit等等，以上数据类型标识的数据大小非常有限，如果遇到大于他们能表示的范围时，计算结果就会有误，日常生活中的计算器也是如此，我国计算两个比较大的数的运算，也会出现错误，或者不能正常显示，
例如计算123456789123456789*987654321987654321
计算结果如下：
具体区别如下：
分析：
在数据运算中会出现两种情况：一种是数据、且小计算结果不会溢出；另一种是数据溢出或者计算结果会溢出；
所以为了计算便捷，也为了节省运算量，我设置了如下两种储存数据方式，并且在计算也分情况不同而选择不同方法，形式如下：
做了什么？
为了解决上述问题，我写了一个计算大数据四则运算以及求模的小项目，实现的功能有 + - * / %；
主要的接口以及实现代码如下：
程序头文件以及接口如下：
/*** 项目名称：大数据运算* 接口名称：BigData.h* 作 者: 邹明* 完成时间：2016.04.12**/#ifndef __BIG_DATA_H__#define __BIG_DATA_H__#includeusing namespace std;#include #include #define MAX_INT64 0x7FFFFFFFFFFFFFFF //小数据能表示的最大值#define MIN_INT64 0x8000000000000000 //小数据能表示的最小值#define INIT 0xcccccccccccccccctypedef long long INT64;class BigData{public: BigData(INT64 value= INIT); BigData(const char*ptrData); //运算符重载 BigData operator+(const BigData& bigdata); BigData operator-(const BigData& bigdata); BigData operator*(const BigData& bigdata); BigData operator/(const BigData& bigdata); BigData operator%(const BigData& bigdata);private: std::string Add(std::string left, std::string right); std::string Sub(std::string left, std::string right); std::string Mul(std::string left, std::string right); std::string Div(std::string left, std::string right); std::string Mod(std::string left, std::string right); //求模 bool IsINT64OverFlow() const; //判断是否越界 void INT64ToString(); //数据转化为字符串 bool IsLeftStrBig(const char *pLeft, int LSise, const char *pRight, int RSise); //比较左操作数是否大于有操作数 char SubLoop(char *pLeft, int LSise, const char *pRight, int RSise); //除法时每次求商运算 friend std::ostream&operator<<(std::ostream & cout, const BigData& bigdata); //输出运算符重载private: INT64 _value; //×××数据形式 string _strData; //字符串数据形式};#endif
实现代码，文件名称BigData.cpp，下面文件晕包含于此内
构造函数，转化字符串，判断越界，输出运算符重载等函数
#include"BigData.h"BigData::BigData(INT64 value) //小数据构造函数 :_value(value){ INT64ToString();}BigData::BigData(const char*ptrData)//大数据构造函数{ //123456 //+1223356 //122334qwer //qwee123 //0000qwer assert(ptrData); char *pstr = (char*)ptrData; char cSymbol = '+'; if (('+' == *pstr) || ('-' == *pstr)) { cSymbol = *pstr; pstr++; } else if (('0' <= *pstr)&&('9' >= *pstr)) { cSymbol = '+'; } else if (*pstr == ' ') { while (*pstr == ' ') { pstr++; } if (('+' == *pstr) || ('-' == *pstr)) { cSymbol = *pstr; pstr++; } else if (('0' <= *pstr) && ('9' >= *pstr)) { cSymbol = '+'; } } else { return; } while (' ' == *pstr) pstr++; while ('0' == *pstr) pstr++; _strData.resize(strlen(ptrData)+1); _strData[0] = cSymbol; _value = 0; int iCount = 1; while ((*pstr >= '0') && (*pstr <= '9')) { _value = _value * 10 + (*pstr - '0'); _strData[iCount] = *pstr; pstr++; iCount++; } _strData.resize(iCount); if (cSymbol == '-') { _value = 0 - _value; }}void BigData::INT64ToString() //将数据的数值填充至字符串部分{ char cSymbl = '+'; if (_value < 0) { cSymbl = '-'; } //1234567 //7654321 _strData.append(1, cSymbl); INT64 temp = _value; if (temp < 0) { temp = 0 - temp; } while (temp) { _strData.append(1, temp % 10 + '0'); temp /= 10; } char *pleft = (char*)_strData.c_str() + 1; char *pright = pleft + _strData.size() - 2; while (pleft < pright) { char tem = *pleft; *pleft = *pright; *pright = tem; pleft++; pright--; }}bool BigData::IsINT64OverFlow()const //判断是否越界{ std::string temp("+9223372036854775807"); if ('-' == _strData[0]) { temp = "-9223372036854775808"; } if (_strData.size() < temp.size()) { return true; } else if ((_strData.size() == temp.size()) && (_strData <= temp)) { return true; } return false;}//求商char BigData::SubLoop(char *pLeft, int LSize, const char *pRight, int RSize){ assert(pLeft); assert(pRight); char cRet = '0'; while (true) { while ((*pLeft == '0')&&LSize>0) { pLeft++; LSize--; } if (!IsLeftStrBig(pLeft, LSize, pRight, RSize)) { break; } for (int i = 1;i<=LSize; i++) { if ((LSize > RSize) && (i == LSize)) { break; } char ret = pLeft[LSize - i]; ret -= pRight[RSize - i]; if (ret < 0) { pLeft[LSize - i - 1] -= 1; ret += 10; } pLeft[LSize - i] = ret+'0'; } cRet++; } return cRet;}//判断左操作数是否大于右操作数bool BigData::IsLeftStrBig(const char *pLeft, int LSise, const char *pRight, int RSise){ if (LSise > RSise || ((LSise == RSise) && (strcmp(pLeft, pRight) >= 0))) { return true; } return false;}//输出运算符重载std::ostream&operator<<(std::ostream & _cout, const BigData& bigdata){ if (bigdata.IsINT64OverFlow()) { _cout << bigdata._value; } else { char *pData = (char*)bigdata._strData.c_str(); if ('+' == pData[0]) { pData++; } _cout << pData; } return _cout;} 加运算
BigData BigData::operator+(const BigData& bigdata) //+ 加法运算符重载{ if (IsINT64OverFlow() && bigdata.IsINT64OverFlow()) { if (_strData[0] != bigdata._strData[0]) { return BigData(_value + bigdata._value); } else { INT64 temp_max = MAX_INT64 - _value; INT64 temp_min = MIN_INT64 - _value; //10 -3 =7 5 //(-10)-(-3)=-7 -5 if (((_value >= 0) && (temp_max >= bigdata._value)) || ((_value < 0) && (temp_min <= bigdata._value))) { return BigData(_value + bigdata._value); } } } if (_strData[0] == bigdata._strData[0]) { return BigData(Add(_strData, bigdata._strData).c_str()); } else { if(_strData[0] == '+') { string ptr(bigdata._strData); ptr[0] = '+'; return Sub(_strData, ptr).c_str(); } else { string ptr(_strData); ptr[0] = '+'; return Sub(bigdata._strData, ptr).c_str(); } }}std::string BigData::Add(std::string left, std::string right){ int iLsize = left.size(); int iRsize = right.size(); char cSymbol = left[0]; //取得符号位 if (iLsize < iRsize) { std::swap(left, right); std::swap(iLsize, iRsize); } std::string sRet; sRet.resize(iLsize + 1); char Step = 0; for (int i = 1; i < iLsize; i++) { char cRet = left[iLsize - i] - '0' + Step; if (i < iRsize) { cRet += (right[iRsize - i] - '0'); } sRet[iLsize - i + 1] = cRet % 10 + '0'; Step = cRet / 10; } sRet[1] = Step + '0'; sRet[0]=cSymbol; return sRet;} 减运算：
BigData BigData::operator-(const BigData& bigdata) //- 减法运算符重载{ if (IsINT64OverFlow() && bigdata.IsINT64OverFlow()) { if (_strData[0] == bigdata._strData[0]) { return BigData(_value - bigdata._value); } else { INT64 temp_max = _value - MAX_INT64; INT64 temp_min = _value - MIN_INT64; //10 -3 =7 5 //(-10)-(-3)=-7 -5 if (((_value >= 0) && (temp_max <= bigdata._value)) || ((_value < 0) && (temp_min >= bigdata._value))) { return BigData(_value - bigdata._value); } } } if (_strData[0] == bigdata._strData[0]) { return BigData(Sub(_strData, bigdata._strData).c_str()); } else { string ptr(bigdata._strData); ptr[0] = _strData[0]; return Add(_strData, ptr).c_str(); }}std::string BigData::Sub(std::string left, std::string right){ int iLsize = left.size(); int iRsize = right.size(); int Max_size = iLsize; std::string sRet; char cSymbol = left[0]; //取符号位 if (iLsize <= iRsize) { if ((iLsize == iRsize) && (strcmp(left.c_str() ,right.c_str())<0) && (left[0] == right[0])) { if ('+' == right[0]) { cSymbol = '-'; } else { cSymbol = '+'; } Max_size = iRsize; std::swap(left, right); std::swap(iLsize, iRsize); } } else { cSymbol = left[0]; Max_size = iLsize; } char Step = 0; sRet.assign(Max_size, 48); for (int i = 1; i < Max_size; i++) { char cRet = 0; if (0<(iLsize - i)) { cRet = left[iLsize - i] - '0' + Step; } if (i < iRsize) { if (cRet < right[iRsize - i] - '0') { cRet += 10; } Step = 0 - (cRet-Step) / 10; cRet -= (right[iRsize - i] - '0'); } sRet[Max_size - i ] = cRet + '0'; } sRet[0] = cSymbol; return sRet;} 乘运算：
BigData BigData::operator*(const BigData& bigdata){ if ((0 == _value)||(0==bigdata._value)) { return BigData(INT64(0)); } if (IsINT64OverFlow() && bigdata.IsINT64OverFlow()) { if (_strData[0] == bigdata._strData[0]) { if (((_value > 0) && ((long long)MAX_INT64 / _value >= bigdata._value)) || ((_value < 0) && ((long long)MAX_INT64 / _value <= bigdata._value))) //同号相乘 结果为正 { return BigData(_value*bigdata._value); } } else { if (((_value > 0) && ((long long)MIN_INT64 / _value <= bigdata._value)) || ((_value < 0) && ((long long)MIN_INT64 / _value >= bigdata._value))) //异号相乘 结果为负 { return BigData(_value*bigdata._value); } } } return BigData(Mul(_strData, bigdata._strData).c_str());}std::string BigData::Mul(std::string left, std::string right){ char cSymbol = '+'; //设置符号位 int iLsize = left.size(); int iRsize = right.size(); if (left[0] == right[0]) cSymbol = '+'; else cSymbol = '-'; if (iLsize > iRsize) { std::swap(left, right); std::swap(iLsize, iRsize); } std::string sRet; int t = 1; if (((left[1] - '0')*(right[1] - '0') +(left[1] - '0')*(right[1] - '0')%10)<10) { t = 2; } else t = 1; //sRet.resize(iLsize + iRsize - t); sRet.assign(iLsize + iRsize - t,'0'); int sizeRet = iLsize + iRsize - 1; sRet[0] = cSymbol; int i = 1, j = 1; for (i = 1, j = 1; i < iLsize; i++) { char step = 0; char cleft = left[iLsize - i] - '0'; for (int j = 1; j < iRsize; j++) { char cRet = cleft*(right[iRsize - j] - '0') + step + (sRet[sizeRet - i - j + 1] - '0'); step = cRet / 10; sRet[sizeRet - i - j + 1] = cRet%10 + '0'; if ((j+1)==iRsize) sRet[sizeRet - i - j] = step+'0'; } } return sRet;} 除运算：
BigData BigData::operator/(const BigData& bigdata){ if (bigdata._strData[1] == '0') { cout << "除数为 0 " << endl; assert(0); } if (_strData[1] == 0) return INT64(0); if ((IsINT64OverFlow()) && bigdata.IsINT64OverFlow()) { return _value / bigdata._value; } if (_strData.size() < bigdata._strData.size()) { return INT64(0); } else if (_strData.size() == bigdata._strData.size()) { if (strcmp(_strData.c_str() + 1, bigdata._strData.c_str() + 1) < 0) return INT64(0); if (strcmp(_strData.c_str() + 1, bigdata._strData.c_str() + 1) == 0) { if (_strData[0] == bigdata._strData[0]) return INT64(1); else return INT64(-1); } } return BigData(Div(_strData, bigdata._strData).c_str());}std::string BigData::Div(std::string left, std::string right){ string sRet; sRet.append(1, '+'); if (left[0] != right[0]) { sRet[0] = '-'; } char *pLeft = (char *)(left.c_str() + 1); char *pRight = (char *)(right.c_str() + 1); int DataLen = right.size() - 1; int Lsize = left.size() - 1; for (int i = 0; i < Lsize; i++) { if (!IsLeftStrBig(pLeft, DataLen, pRight, right.size()-1)) { sRet.append(1, '0'); DataLen++; } else { sRet.append(1, SubLoop(pLeft, DataLen, pRight, right.size() - 1)); } if (DataLen + i>Lsize) { break; } if (*pLeft == '0') { pLeft++; } else { DataLen = right.size(); } } return sRet;} 摸除运算：
BigData BigData:: operator%(const BigData& bigdata){ if (bigdata._strData[1] == '0') { cout << "除数为 0 或对0求模" << endl; assert(0); } if (_strData[1] == 0) return INT64(0); if ((IsINT64OverFlow()) && bigdata.IsINT64OverFlow()) { return _value % bigdata._value; } if (_strData.size() < bigdata._strData.size()) { return BigData(_strData.c_str()); } else if (_strData.size() == bigdata._strData.size()) { if (strcmp(_strData.c_str() + 1, bigdata._strData.c_str() + 1) < 0) return INT64(0); if (strcmp(_strData.c_str() + 1, bigdata._strData.c_str() + 1) == 0) { return INT64(0); } } return BigData(Mod(_strData, bigdata._strData).c_str());}std::string BigData::Mod(std::string left, std::string right){ char cSymbol = left[0]; BigData n1(left.c_str() + 1); BigData n2(right.c_str() + 1); BigData n3 = n1 / n2; BigData n4 = n3*n2; BigData sRet(n1 - n4); sRet._strData[0] = cSymbol; return sRet._strData;} 测试用例，文件名test.cpp
#include"BigData.h"void Test1(){ BigData n1(123456); BigData b2("12346678"); BigData b3("+12346678"); BigData b4("-123466"); BigData b5("+"); BigData b6(" "); BigData b7("12346aaaa"); BigData b8("+asd12346678"); BigData b9("000012346678"); cout << "n1:" << n1 << endl; cout << "b2:" << b2 << endl; cout << "b3:" << b3 << endl; cout << "b4:" << b4 << endl; cout << "b5:" << b5 << endl; cout << "b6:" << b6 << endl; cout << "b7:" << b7 << endl; cout << "b8:" << b8 << endl; cout << "b9:" << b9 << endl;}void testAdd(){ BigData b1("-45353"); BigData b2("37353753"); BigData b3("- 9223372036854775808"); BigData b4(" 9223372036854775800"); BigData b5(" -9223372036854775810"); BigData b6("9223372036854775900"); //1、都在INT64范围内 cout << (b1 + b1) << endl; cout << (b2 + b2) << endl; cout << (b1 + b2) << endl; cout << "b4:" << b4 << endl; cout << (b1 + b4) << endl; cout << b3 << endl; cout << (b1 + b3) << endl; cout << (b2 + b4) << endl; //2、都不在INT64范围内 cout << (b2 + b5) << endl; cout << (b1 + b6) << endl; cout << (b6 + b1) << endl;}void testSub(){ BigData b1("-45353"); BigData b2("37353753"); BigData b3("-9223372036854775808"); BigData b4("9223372036854775800"); BigData b5("-9223372036854775810"); BigData b6("9223372036854775900"); //1、都在INT64范围内 cout << (b1 - b2) << endl; cout << (b2 - b1) << endl; cout << (b3 - b1) << endl; cout << (b1 - b4) << endl; cout << (b3 - b2) << endl; cout << (b4 - b1) << endl; cout << (b1 - b3) << endl; cout << (b2 - b4) << endl; cout << endl; //2、一个在一个不在 <运算后在范围内，运算后不在范围内> cout << (b5 - b1) << endl; cout << (b1 - b5) << endl; cout << endl; cout << (b6 - b2) << endl; cout << (b2 - b6) << endl; cout << endl; cout << (b6 - b5) << endl; cout << (b5 - b6) << endl; cout << (b2 - b5) << endl; cout << (b1 - b6) << endl; cout << (b6 - b1) << endl;}void testMul(){ BigData b1("-45353"); BigData b2("37353753"); BigData b3("-9223372036854775808"); BigData b4(" 9223372036854775800"); BigData b5("-9223372036854775810"); BigData b6(" 9223372036854775900"); //1、都在INT64范围内 cout << (BigData("999") * BigData("22222222222222222222222222222")) << endl; cout << (b2 * b1) << endl; cout << (b1 * b2) << endl; cout << (b1 * BigData("0")) << endl; cout << (BigData("0") * b2) << endl; cout << endl; cout << (b3 * b1) << endl; cout << (b1 * b3) << endl; cout << (b1 * b4) << endl; cout << (b4 * b1) << endl; cout << (b3 * b2) << endl; cout << (b2 * b4) << endl; cout << endl; //2、一个在一个不在 <运算后在范围内，运算后不在范围内> cout << (BigData("0") * b6) << endl; cout << (b5 * BigData("0")) << endl; cout << (b5 * b1) << endl; cout << (b1* b5) << endl; cout << endl; cout << (b6 * b2) << endl; cout << (b2 * b6) << endl; cout << endl; cout << (b6 * b5) << endl; cout << (b5 * b6) << endl; cout << (b2 * b5) << endl; cout << endl; cout << (b1 * b6) << endl; cout << (b6 * b1) << endl;}void testDiv(){ BigData b1("-45353"); BigData b2("37353753"); BigData b3("-9223372036854775808"); BigData b4(" 9223372036854775800"); BigData b5("-9223372036854775810"); BigData b6(" 9223372036854775900"); BigData b7("-1231123203367738338252"); //1、排除除数为0 cout << (b1 / BigData(0)) << endl; //2、在范围内 cout << (b1 / b2) << endl; cout << (b2 / b1) << endl; //3、不在范围内 <左（被除数）比右（除数）小为0，左比右大> cout << (b2 / b5) << endl; cout << (b2 / b6) << endl; cout << (b5 / b2) << endl; cout << (b6 / b2) << endl; cout << (b6 / b1) << endl; cout << (b5 / b1) << endl; cout << b7 / b1 << endl;}void testMod(){ BigData b1("-45353"); BigData b2("37353753"); BigData b3("-9223372036854775808"); BigData b4(" 9223372036854775800"); BigData b5("-9223372036854775810"); BigData b6(" 9223372036854775900"); BigData b7("-1231123203367738338252"); //1、排除除数为0 cout << (b1 / BigData(0)) << endl; //2、在范围内 cout << (b1 % b2) << endl; cout << (b2 % b1) << endl; //3、不在范围内 cout << (b2 % b5) << endl; cout << (b2 % b6) << endl; cout << (b5 % b2) << endl; cout << (b6 % b2) << endl; cout << (b6 % b1) << endl; cout << (b5 % b1) << endl; cout << b7 % b1 << endl;}int main(){ //testAdd(); //测试+ //testSub(); //测试- //testMul(); //测试 * //testDiv(); //测试 / testMod(); //测试% system("pause"); return 0;} 运行结果：
加运算：
减运算：
乘运算：
除运算：
模除运算：
以上代码均为原创，实现了与小数据运算同样的功能，如果发现错误，欢迎各位读者批评指正，谢谢