用java或者C++实现一个堆栈类

//用java或者C++实现一个堆栈类，并考虑异常实现思想：用链表实现的一个栈的操作，可以跟据栈的元素个数动态分配内存尚未在vc环境下调试，算是伪码吧Struct Node{int entry;int *next;Node();Node(int item, Node *add_on = NULL);};Node::Node(){next = NULL;}Node::Node(int item, Node *add_on){entry = item;next = add_on;}Class Stack{public:Stack();Stack(Node &item);~Stack();Error_code push(int item);Error_code pop();Error_code top(int &item);bool empty();private:Node *topNode;};Stack::Stack(){topNode = NULL;}Stack::~Stack(){while(!empty()){pop();}}//简单的单向链表，每次新建一个元素都链到栈顶Stack::Stack(Node &item){Node *oriangle = item.topNode;Node *newTop;Node *newCopy;if(!oriangle){return;}else{newCopy = new Node(oriangle->entry);newTop = newCopy;oriangle = oriangle->next;while(oriangle){newCopy->next = new Node(oriangle->entry);newCopy = newCopy->next;oriangle = oriangle->next;}}topNode = newTop;}//把item 挂到最新的topNode下面Error_code Stack::push(int item){Node *newNode;newNode = newNode(item, topNode);if (!newNode){return overflow;}topNode = newNode;return success;}//每次都取栈顶Error_code Stack::pop(){Node *oldNode = topNode;if (!topNode){return underflow;}topNode = topNode->next;delete oldNode;return success;}//当前的topNode 为空，则为空bool Stack::empty(){return topNode == NULL;}Error_code top(int &item){if (!topNode){return underflow;}item = topNode->entry;return success;}