内存泄漏-STL集 [英] Memory Leaks - STL sets

问题描述

我正试图解决我所有的内存泄漏问题(这是巨大的).我是STL的新手.我有一个班级图书馆，那里有3套.我还在库类中使用new来创建大量内存，以向集合中添加信息...

I am trying to plug up all my memory leaks (which is massive). I am new to STL. I have a class library where I have 3 sets. I am also creating a lot of memory with new in the library class for adding info to the sets...

我需要取消分配集合吗?如果可以，怎么办?

Do I need to deallocate the sets? If so, how?

这是图书馆.h

    #pragma once

#include <ostream>
#include <map>
#include <set>
#include <string>
#include "Item.h"

using namespace std;

typedef set<Item*>              ItemSet;
typedef map<string,Item*>       ItemMap;
typedef map<string,ItemSet*>    ItemSetMap;

class Library
{

public:
    // general functions

    void addKeywordForItem(const Item* const item, const string& keyword);
    const ItemSet* itemsForKeyword(const string& keyword) const;
    void printItem(ostream& out, const Item* const item) const;

    // book-related functions

    const Item* addBook(const string& title, const string& author, int const nPages);
    const ItemSet* booksByAuthor(const string& author) const;
    const ItemSet* books() const;

    // music-related functions

    const Item* addMusicCD(const string& title, const string& band, const int nSongs);
    void addBandMember(const Item* const musicCD, const string& member);
    const ItemSet* musicByBand(const string& band) const;
    const ItemSet* musicByMusician(const string& musician) const;
    const ItemSet* musicCDs() const;

    // movie-related functions

    const Item* addMovieDVD(const string& title, const string& director, const int nScenes);
    void addCastMember(const Item* const movie, const string& member);
    const ItemSet* moviesByDirector(const string& director) const;
    const ItemSet* moviesByActor(const string& actor) const;
    const ItemSet* movies() const;
    ~Library();
};

我不确定要为析构函数做什么?

I am not sure what i need to do for the destructor?

Library::~Library()
{


}

另外，我是否要分配字符串集正确?

also, am I de allocating the stringset right?

    #ifndef CD_H
#define CD_H
#pragma once
#include "item.h"
#include <set>


typedef set<string> StringSet;


class CD : public Item
{
public:

    CD(const string& theTitle, const string& theBand, const int snumber);
    void addBandMember(const string& member);
    const int getNumber() const;
    const StringSet* getMusician() const;
    const string getBand() const;
    virtual void print(ostream& out) const;
    string printmusicians(const StringSet* musicians) const;

    ~CD();


private:

    string band;
    StringSet* music;

    string title;
    int number;

};

ostream& operator<<(ostream& out, const CD* cd);

#endif

cd.cpp

    #include "CD.h"

using namespace std;

CD::CD(const string& theTitle, const string& theBand, const int snumber)
: Item(theTitle), band(theBand),number(snumber), music(new StringSet)
{



}

CD::~CD()
{

    delete []music;

}

在库类中，我正在创建大量内存，但是析构函数不会清除这些内存吗? 例如:

in the library class I am creating a lot of memory, but dont the destructor clean that up? example:

    const Item* Library::addBook(const string& title, const string& author, const int nPages)
{

    ItemSet* obj = new ItemSet();
    Book* item = new Book(title,author,nPages);
    allBooks.insert(item); // add to set of all books
    obj->insert(item);

注意:我没有副本构造函数.我不确定我是否需要一个，或者顶部如何添加一个.我也不认为我的析构函数会被调用.

Note: I do not have a copy constructor. I am not sure if I even need one or how top add one. I dont think my destructors are getting called either..

推荐答案

您需要释放集合中每个元素的内存.容器不会为您这样做，也不应该这样做，因为它不知道自己是否拥有该数据，它可能只是持有指向其他对象拥有的对象的指针.

You need to free the memory for each element of the set. The container will not do that for you, and it shouldn't because it can't know whether it owns that data or not -- it could just be holding pointers to objects owned by something else.

这是一个通用的免费函数，它将取消分配任何STL容器.

This is a generic free function that will deallocate any STL container.

template <typename T>
void deallocate_container(T& c)
{
  for (typename T::iterator i = c.begin(); i != c.end(); ++i)
    delete *i;
}

// Usage
set<SomeType*> my_set;
deallocate_container(my_set);
my_set.clear();

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