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带有链表的C++堆栈-内存错误?

linked-list stack c++

Johnrad · 技术社区 · 15 年前

我目前正在编写一个正在使用链表实现的堆栈。我得到这个错误:

Unhandled exception at 0x75249617 in STACK_LinkedList.exe: Microsoft C++ exception: std::bad_alloc at memory location 0x002ee8f8.

push() 或 pop() 功能。我找不到我的错误。我对链表还很陌生,所以我很难找到错误。

推() 功能:

// Adds an item to the top of the stack
template <class S>
void Stack<S>::push(const S & e)
{
    NodePointer temp = new Node(e);

    if ( isEmpty() )
    {
        theTop = theFront = temp;
    }
    else
    {
            // Whatever is after top is stored in temp to keep track of it
        theTop->next = temp;

            // TheTop is stored in temp
        theTop = temp;  
        delete temp; 
    }
}

这是我的功能:

//Takes the item off the top of the stack
template <class S>
void Stack<S>::pop()
{
    if ( !isEmpty() )
    {        
                //temp node is set equal to the front
        NodePointer temp = theFront;

                //Holds the second to last node in the linked list
        NodePointer pred;

                //loops through until the node after temp is 0
        while (temp->next != 0)
        {
                        //sets the second to last as temp
            pred = temp ;

                        //basically "increments" temp to the next node
            temp = temp->next ;
        }

                //sets temp equal to the top
        temp = theTop;

                //the top is then set to its predecessor
        theTop = pred;

                //deletes what was known as the top
        delete temp;
    }

    else
        cout << "STACK IS EMPTY" << endl;

}

2 回复 | 直到 15 年前

Vlad 15 年前

你不应该删除 temp 在里面 push ! 这是名单的一部分。因此,当您稍后访问这些数据时,肯定会出现异常。

其次,必须初始化 pred NULL 在里面 pop() ,否则将得到一个未定义的值 theTop

第三,你应该删除 弹出() 在中分配的节点 push() .

弹出() . 你的代码应该是这样的:

void push(data)
{
    allocate new top
    new top's next is the old top
    store new top in the class
}

void pop()
{
    if empty, ERROR;
    new top = old top's next
    deallocate old top
}

注意你不需要 theFront