template<class T>
struct node
{
  T value; //储存的值
  node<T>* next; 

  node() :next(nullptr){} //构造函数
  node(T t) :value(t), next(nullptr){}
};

template<class T>
class myStack
{
  int cnts; //入栈数量
  node<T> *head; //栈的头部
public:

  myStack(){ cnts = 0; head = new node<T>; }
  void stackPush(T arg); //入栈
  T stackPop(); //出栈
  T stackTop(); //获取栈顶元素

  void printStack(); //打印栈
  int counts(); //获取栈内元素个数
  bool isEmpty(); //判断空
};
template<class T>
void myStack<T>::stackPush(T arg)
{
  node<T> *pnode = new node<T>(arg); //申请入栈元素的空间
  pnode->next = head->next;
  head->next = pnode;
  cnts++;
}
template<class T>
T myStack<T>::stackPop()
{
  if (head->next!=nullptr) 
  {
    node<T>* temp = head->next;
    head->next = head->next->next;
    T popVal = temp->value;
    delete temp;
    return popVal;
  }
}
template<class T>
T myStack<T>::stackTop()
{
  if (head->next!=nullptr)
  {
    return head->next->value;
  }
}
template<class T>
void myStack<T>::printStack()
{
  if (head->next != nullptr)
  {
    node<T>* temp = head;
    while (temp->next != nullptr)
    {
      temp = temp->next;
      cout << temp->value << endl;
    }
  }
}
template<class T>
int myStack<T>::counts()
{
  return cnts;
}
template<class T>
bool myStack<T>::isEmpty()
{
  if (cnts)
    return false;
  else
    return true;
}