c++ - 在 C++ 中从堆栈中弹出一个数字？

Question

到目前为止我的代码是...

struct stack_struct
{
    int number;
    struct stack_struct *next_number;
};

stack_struct *mainStruct;

class stack_class
{
private:

    struct stack_struct *head;

public:
    stack_class();
    ~stack_class();
    void pushNumber(int number);
    void popNumber();
    void findNumber();
    void clearStack();
    void sizeFinder();
    void printStack();
    void reverseStack();//Extra Credit
};
stack_class mainClassStack;

stack_struct *pointerFunc,*tailPointer=NULL,*pointerFunc3,*printPointer;

stack_class::stack_class()
{
    head=NULL;
}

stack_class::~stack_class()
{
    clearStack();
    cout<<"\nList Cleared.\n";
    system("pause");
}


void stack_class::popNumber()
{
    stack_struct *pointerPop=NULL,*pointerPop2=NULL;
    int popCounter=0,i=0;
    pointerPop2=tailPointer;
    if(head==NULL)
    {
        cout<<"\nNo Member to Delete.\n";
    }
    else
    {
        while(pointerPop2)
        {
            popCounter++;
            //cout<<pointerFunc3->number<<endl;
            pointerPop2=pointerPop2->next_number;
        }
        pointerPop=tailPointer;
        while(i<(popCounter-2))
        {
            pointerPop=pointerPop->next_number;
            i++;
        }
        pointerPop->next_number=NULL;
        delete head;
        head=pointerPop;
    }

}

void stack_class::printStack()
{
    pointerFunc3=tailPointer;
    if(tailPointer==NULL)
    {
        cout<<"\nNo Members in List.\n";
    }
    else
    {
        cout<<"\n\nList Is:\n";
        while(pointerFunc3)
        {
            cout<<pointerFunc3->number<<endl;
            pointerFunc3=pointerFunc3->next_number;
        }
    }

}

只要不是最后一个数字，弹出就可以正常工作。如果弹出最后一个数字(列表为空)，并且我尝试打印列表，程序会无限打印垃圾。如果我在列表为空后尝试弹出一个数字，程序会卡住。我该如何解决这些问题？

Answer 1

你也可以创建一个虚拟节点来解决这个问题。否则:

int stack_class::popNumber()
{
    如果(头==空)
        throw new Exception("堆栈为空");
    int result = head->number;
    删除头；
    head = head->next_number;
    返回结果；
}

void stack_class::pushNumber(整数)
{
    stack_struct *elem= new stack_struct();
    元素->数字=数字；
    elem->next_number = head;
    头=元素；
}

!!!!!尽量不要使用全局变量，例如 (stack_class mainClassStack;

stack_struct *pointerFunc,*tailPointer=NULL,)