數(shù)據(jù)結(jié)構(gòu)--異常類與頂層父類的實(shí)現(xiàn)

一 C++異常的簡介

C++內(nèi)置了異常處理的語法元素try.....catch.....
1.try語句處理正常代碼邏輯
2.catch語句處理異常情況
3.try語句中的異常由對應(yīng)的catch語句處理
常見的語句如下

try
{
    double r=divide(1,0);
}
catch(...)
{
    cout<<"the result..."<<endl;
}

C++通過throw語句拋出異常信息

double divide(double a,double b)
{
    const double delta=0.00000000001;
    double ret=0;

    if(!((-delta<b)&&(b<delta)))
    {
        ret=a/b;
    }
    else
    {
        throw 0;//產(chǎn)生除0異常
     }
    return ret;
}

C++異常處理分析
throw拋出的異常必須被catch處理--當(dāng)前函數(shù)能夠處理異常，程序機(jī)械往下執(zhí)行，當(dāng)前函數(shù)無法處理異常，則函數(shù)停止執(zhí)行，并返回.未被處理的異常會順著函數(shù)調(diào)用棧向上傳播，直到被處理為止，否則程序?qū)⑼Ｖ箞?zhí)行

//代碼示例
#include <iostream>
using namespace std;
double divide(double a, double b)
{
    const double delta = 0.000000000000001;
    double ret = 0;

    if( !((-delta < b) && (b < delta)) ) {
        ret = a / b;
    }
    else {
        throw 0;   // 產(chǎn)生除 0 異常
    }

    return ret;
}

void Demo1()
{
    try
    {
        throw 'c';
    }
    catch(int i)
    {
        cout << "catch(int i)" << endl;
    }
    catch(double d)
    {
        cout << "catch(double d)" << endl;
    }
    catch(char c)
    {
        cout << "catch(char c)" << endl;
    }
}

void Demo2()
{
    throw 0.0001; // "D.T.Software";   // const char*
}

int main()
{
    cout << "main() begin" << endl;

    try
    {
        double c = divide(1, 1);

        cout << "c = " << c << endl;
    }
    catch(...)
    {
        cout << "Divided by zero..."  << endl;
    }

    Demo1();

    try
    {
        Demo2();
    }
    catch(char* c)
    {
        cout << "catch(char* c)" << endl;
    }
    catch(const char* cc)
    {
        cout << "catch(char* cc)" << endl;
    }
    catch(...)
    {
        cout << "catch(...)" << endl;
    }

    cout << "main() end" << endl;

    return 0;
}

二 異常類的構(gòu)建

異常的類型可以是自定義類類型，對于類類型異常的匹配依舊是至上而下嚴(yán)格匹配，賦值兼容性原則在異常匹配中依然適用
異常類的功能定義

#ifndef EXCEPTION_H
#define EXCEPTION_H
/*
   異常的類型可以是自定義類類型
   對于類類型異常的匹配依舊是至上而下嚴(yán)格匹配

   一般而言
      匹配子類異常的catch放在上部
      匹配父類異常的catch放在下部
 */
#include "Object.h"

namespace MyLib
{
//定義宏THROW_EXCEPTION，拋出異常時直接寫異常類型及異常信息即可
#define THROW_EXCEPTION(e, m) (throw e(m, __FILE__, __LINE__))

    class Exception:public Object
    {
    protected:
        char* m_message;//異常的信息
        char* m_location;//異常的位置

        void init(const char* message,const char *file,int line);
    public:
        Exception(const char* message);
        Exception(const char *file,int line);
        Exception(const char* message,const char *file,int line);

        Exception(const Exception& e);
        Exception& operator=(const Exception& e);

        virtual const char* message()const;
        virtual const char* location()const;

         virtual ~Exception();//純虛函數(shù)
    };

    class ArithmeticException : public  Exception
    {
    public:
        ArithmeticException():Exception(0){}
        ArithmeticException(const char* message):Exception(message){}
        ArithmeticException(const char* file,int line):Exception(file,line){}
        ArithmeticException(const char*message,const char*file,int line):Exception(message,file,line){}

        ArithmeticException(const ArithmeticException& e):Exception(e){}//拷貝構(gòu)造函數(shù)

        ArithmeticException&operator =(const ArithmeticException& e)
        {
            Exception::operator =(e);
            return *this;
        }
    };

    class NullPointerException : public Exception
    {
    public:
        NullPointerException():Exception(0){}
        NullPointerException(const char* message):Exception(message){}
        NullPointerException(const char* file,int line):Exception(file,line){}
        NullPointerException(const char*message,const char*file,int line):Exception(message,file,line){}

        NullPointerException(const NullPointerException& e):Exception(e){}//拷貝構(gòu)造函數(shù)

        NullPointerException&operator =(const NullPointerException& e)
        {
            Exception::operator =(e);
            return *this;
        }
    };

    class indexOutOfBoundsException : public Exception
    {
    public:
        indexOutOfBoundsException():Exception(0){}
        indexOutOfBoundsException(const char* message):Exception(message){}
        indexOutOfBoundsException(const char* file,int line):Exception(file,line){}
        indexOutOfBoundsException(const char*message,const char*file,int line):Exception(message,file,line){}

        indexOutOfBoundsException(const indexOutOfBoundsException& e):Exception(e){}//拷貝構(gòu)造函數(shù)

        indexOutOfBoundsException&operator =(const indexOutOfBoundsException& e)
        {
            Exception::operator =(e);
            return *this;
        }
    };

    class NoEoughMemoryException : public Exception
    {
    public:
        NoEoughMemoryException():Exception(0){}
        NoEoughMemoryException(const char* message):Exception(message){}
        NoEoughMemoryException(const char* file,int line):Exception(file,line){}
        NoEoughMemoryException(const char*message,const char*file,int line):Exception(message,file,line){}

        NoEoughMemoryException(const NoEoughMemoryException& e):Exception(e){}//拷貝構(gòu)造函數(shù)

        NoEoughMemoryException&operator =(const NoEoughMemoryException& e)
        {
            Exception::operator =(e);
            return *this;
        }
    };

    class InvalidOperationException : public Exception
    {
    public:
        InvalidOperationException():Exception(0){}
        InvalidOperationException(const char* message):Exception(message){}
        InvalidOperationException(const char* file,int line):Exception(file,line){}
        InvalidOperationException(const char*message,const char*file,int line):Exception(message,file,line){}

        InvalidOperationException(const InvalidOperationException& e):Exception(e){}//拷貝構(gòu)造函數(shù)

        InvalidOperationException&operator =(const InvalidOperationException& e)
        {
            Exception::operator =(e);
            return *this;
        }
    };

    class InvalidParameterException : public Exception
    {
    public:
        InvalidParameterException():Exception(0){}
        InvalidParameterException(const char* message):Exception(message){}
        InvalidParameterException(const char* file,int line):Exception(file,line){}
        InvalidParameterException(const char*message,const char*file,int line):Exception(message,file,line){}

        InvalidParameterException(const InvalidParameterException& e):Exception(e){}//拷貝構(gòu)造函數(shù)

        InvalidParameterException&operator =(const InvalidParameterException& e)
        {
            Exception::operator =(e);
            return *this;
        }
    };
}
#endif // EXCEPTION_H

三 頂層父類的創(chuàng)建
創(chuàng)建頂層父類的意義--遵循經(jīng)典設(shè)計準(zhǔn)則，所有的數(shù)據(jù)都繼承Object類，定義動態(tài)內(nèi)存申請的行為，提高代碼的移植性
頂層父類的接口定義

    class Object
    {
          public:
            void* operator new(unsigned int size)throw();
            void operator delete(void* p);
            void* operator new[](unsigned int size)throw();
            void operator delete[](void* p);

            ~Object();
    };
        /*
        Object類是所寫的頂層父類
        Object類用于統(tǒng)一內(nèi)存申請的行為
        在堆中創(chuàng)建Object子類的對象，失敗時返回NULL值
        Object類為純虛父類，所有子類都能進(jìn)行動態(tài)類型識別
        */