Question

我试图尽可能释放内存，但在调用delete时我会一直触发断点。自从我完成c ++以来已经有一段时间了，所以我不记得确切的方法。

的main.cpp

int _tmain(int argc, _TCHAR* argv[])
{
    LIFO lifo = *new LIFO();

    LIFO::Element element1  = *new LIFO::Element(1);
    LIFO::Element element2  = *new LIFO::Element(2);
    LIFO::Element element3  = *new LIFO::Element(3);
    LIFO::Element element4  = *new LIFO::Element(4);
    LIFO::Element element5  = *new LIFO::Element(5);
    LIFO::Element element6  = *new LIFO::Element(6);

    lifo.Push(element1);
    lifo.Push(element2);
    lifo.Push(element3);
    lifo.Push(element4);
    lifo.Push(element5);
    lifo.Push(element6);

    lifo.Peek(lifo.mSize);

    lifo.Pop();
    lifo.Pop();
    lifo.Pop();

    lifo.Peek(lifo.mSize);

    lifo.Push(element1);
    lifo.Push(element2);
    lifo.Push(element3);
    lifo.Push(element4);
    lifo.Push(element5);
    lifo.Push(element6);

    lifo.Peek(lifo.mSize);

    lifo.Empty();

    lifo.Peek(lifo.mSize);

    return 0;
}

LIFO.h

class LIFO
{
public:

    unsigned int mSize;

    LIFO(void)
        :mSize(0)
    {
        mTop = nullptr;
    }


    ~LIFO(void)
    {

    }

    class Element
    {
    public:
        Element* mNextElement;
        int mData;

        Element()
            :mData(0)
            ,mNextElement(nullptr)
        {

        }

        Element(int data)
            :mData(data)
            ,mNextElement(nullptr)
        {

        }

        ~Element()
        {

        }

    };

    Element* mTop;

    void Push(Element& element)
    {
        if(mTop != nullptr)
        {
            Element* newElement = &element;
            newElement->mNextElement = mTop;
            mTop = newElement;

            delete newElement;
            newElement = nullptr;
        }
        else
        {
            mTop = &element;
        }

        ++mSize;
    }

    void Pop()
    {
        if(mTop != nullptr)
        {
            Element* oldElement = mTop;
            mTop = mTop->mNextElement;
            --mSize;

            delete oldElement;
            oldElement = nullptr;
        }
    }

    void Empty()
    {
        while(mTop != nullptr)
        {
            Pop();
        }
    }

    void Peek(unsigned int depth)
    {
        Element* current = mTop;

        for(unsigned int i = 0; i < depth; ++i)
        {
            if(current != nullptr)
            {
                std::cout << current->mData << '\n';

                if(current->mNextElement != nullptr)
                {
                    current = current->mNextElement;
                }
                else
                {
                    break;
                }
            }
            else
            {
                break;
            }
        }

        delete current;
        current = nullptr;
    }

};

我也曾在析构函数中尝试过这些并且它们都没有正常工作

~LIFO(void)
{
    Element* current = mTop;

    while(current != nullptr)
    {
        Element* next = current->mNextElement;
        delete current;
        current = next;
    }

    current = nullptr;
}

如何在此堆栈中安全释放内存？

Answer 1

您对Peek的理解是错误的。 Peek不会删除堆栈中的任何元素。在Peek中删除删除语句。但是界面仍然是错误的。

来推，尝试这个修改过的Push。

void Push(Element* element)
{
    if(mTop != nullptr)
    {
        Element* currTop = mTop;            
        element->mNextElement = currTop;
        mTop = element;            
    }
    else
    {
        mTop = element;
    }
    ++mSize;
}

现在你的课程的使用应该是

LIFO* lifo = new LIFO();
LIFO::Element* element1  = new LIFO::Element(1);

析构函数~Lifo()中的代码很好。完成堆栈操作后，使用语句delete lifo;删除lifo。

关于删除堆栈中的指针感到困惑

1 个答案: