C ++虚拟析构函数-内存泄漏

basf bfnsa

我很难弄清楚如何解决以下问题:

#include "stdafx.h"
using namespace std;
#define CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>

class Talker
{
public:
    virtual void SaySomething() = 0;
};

class SoundProducer
{
protected:
    string soundName;
public:
    SoundProducer(string nameOfSound)
    {
        this->soundName = nameOfSound;      
    }

    virtual void MakeSound() = 0;

    string GetSoundName()
    {
        return this->soundName;
    }
};

class Uppgift1 : public Talker
{
private:
    SoundProducer* t;

public:
    Uppgift1(){};

    void SetSoundProducer(SoundProducer* _soundProducer)
    {
        t = _soundProducer;
    }

    void SaySomething()
    {
        t->MakeSound();
    }

    virtual ~Uppgift1()
    {
        delete t;
    }
};

class Whisperer : public SoundProducer
{
public:
    Whisperer() : SoundProducer("Whisper"){}

    virtual void MakeSound()
    {
        cout << soundName << ": Ssch,hush,hush" << endl;
    }

    virtual ~Whisperer()
    {
        cout << "Whisperer destructor called" << endl;
    }
};

class Shouter : public SoundProducer
{
public:
    Shouter() : SoundProducer("Shout"){}

    virtual void MakeSound()
    {
        cout << soundName << ": WOW YEEEH!!" << endl;
    }

    virtual ~Shouter()
    {
        cout << "Shouter destructor called" << endl;
    }
};

int main()
{
    Uppgift1 uppg1;
    uppg1.SetSoundProducer(new Whisperer);
    uppg1.SaySomething();
    uppg1.SetSoundProducer(new Shouter);
    uppg1.SaySomething();

    _CrtDumpMemoryLeaks();
    return 0;
}

我遇到的问题是内存泄漏,并且我试图找出在超出范围时如何删除指向类的指针。

至于现在,喊叫和低语者不会被删除,这会导致内存泄漏。

看起来唯一的方法是使SoundProducer类继承uppgift1类并将析构函数虚拟化,对吗?我有点累了,如果也让您感到困惑,也很抱歉:)

basav

您将声音产生器设置了两次,但是UppGift只能容纳一个...。因此,将调用Shouter的析构函数,因为它是最后添加的元素,并且从未调用过Whsperer的析构函数,因为您已经将其再次设置为Shouter。

前:

Uppgift1 uppg1;
uppg1.SetSoundProducer(new Whisperer);
uppg1.SaySomething();
uppg1.SetSoundProducer(new Shouter);

您两次拨打电话,但只能保留一个。

SoundProducer* t;

后:

如果要添加多个SoundProducer,请维护它们的列表/矢量。

vector<SoundProducer*> _list;

    virtual ~Uppgift1()
    {
    //    delete t;
     std::vector< SoundProducer*>::iterator it = _list.begin();
    //delete *it;
  for ( ; it != _list.end(); it++ ) 
  {
            delete *it;

  }
_list.clear(); 

在继承树中,如果您尝试通过基指针删除派生类实例,则基类析构函数应该是虚拟的。这样,当您对指向派生类实例I的基类指针进行删除时,派生类析构函数将被调用现在已经编辑了代码。

#include <iostream>

using namespace std;
#define CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <vector>
//#include <crtdbg.h>

class Talker
{
public:
    virtual void SaySomething() = 0;
    virtual ~Talker(){cout<<"Talker Destructor"<<endl;}
};

class SoundProducer
{
protected:
    string soundName;
public:
    SoundProducer(string nameOfSound)
    {
        this->soundName = nameOfSound;      
    }

    virtual void MakeSound() = 0;

    string GetSoundName()
    {
        return this->soundName;
    }
    virtual ~SoundProducer(){cout<<"SoundProducer Detructor"<<endl;}
};

class Uppgift1 : public Talker
{
private:
    SoundProducer* t;
     vector<SoundProducer*> _list;
public:
    Uppgift1(){};

    void SetSoundProducer(SoundProducer* _soundProducer)
    {
        if(_soundProducer)
      {  cout<<"pushing into list"<<endl;
        _list.push_back(_soundProducer);
      }
     //   t = _soundProducer;
    }

    void SaySomething()
    {
       // t->MakeSound();
    }

    virtual ~Uppgift1()
    {
    //    delete t;
     std::vector< SoundProducer*>::iterator it = _list.begin();
    //delete *it;
  for ( ; it != _list.end(); it++ ) 
  {
            delete *it;

  }
_list.clear(); 


    }


};

class Whisperer : public SoundProducer
{
public:
    Whisperer() : SoundProducer("Whisper"){}

    virtual void MakeSound()
    {
        cout << soundName << ": Ssch,hush,hush" << endl;
    }

    virtual ~Whisperer()
    {
        cout << "Whisperer destructor called" << endl;
    }
};

class Shouter : public SoundProducer
{
public:
    Shouter() : SoundProducer("Shout"){}

    virtual void MakeSound()
    {
        cout << soundName << ": WOW YEEEH!!" << endl;
    }

    virtual ~Shouter()
    {
        cout << "Shouter destructor called" << endl;
    }
};

int main()
{
    Uppgift1 uppg1;
    SoundProducer* ptr=new Whisperer;
    uppg1.SetSoundProducer(dynamic_cast<SoundProducer*>(ptr));
    uppg1.SaySomething();
    uppg1.SetSoundProducer(new Shouter);
    uppg1.SaySomething();

 //   _CrtDumpMemoryLeaks();
    return 0;
}

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