栈 C++ 适用各种数据类型，，仿Java API

#ifndef STACK_HH#define STACK_HH#include<iostream>#include<stdlib.h>using namespace std;template <typename type>struct StackNode{    type value;    StackNode *next;    StackNode *previous;};template <typename type>class Stack{private:    int len;    StackNode<type> *top;    StackNode<type> *head;    StackNode<type> *tail;    bool isReverse;public:    Stack();    ~Stack();    bool isEmpty();    bool push(type value);    type pop();    type getTop();    bool reverse();    bool isReversed();    int getLength();};template <typename type>Stack<type>::Stack(){    top = NULL;    len = -1;    isReverse = false;}template <typename type>bool Stack<type>::isEmpty(){    if(this->len == -1 || this->top == NULL)    {        return true;    }    return false;}template <typename type>bool Stack<type>::push(type value){    StackNode<type> *vNode = new StackNode<type>();    vNode->value = value;    if(vNode == NULL)    {        return false;    }    if(len == -1 || this->top == NULL)    {        top = vNode;        top->next = NULL;        top->previous = NULL;        this->head = vNode;        this->tail = vNode;        this->len++;        return true;    }    //if the stack was reversed    if(this->isReverse)    {        vNode->previous = this->tail;        this->tail->next = vNode;        this->tail = vNode;        this->top = this->tail;    }    else    {        vNode->next = this->head;        this->head ->previous = vNode;        this->head = vNode;        this->top = this->head;    }    this->len++;    return true;}template <typename type>type Stack<type>::pop(){    if(len == -1 || this->top == NULL)    {        return NULL;    }    type temp = this->top->value;    StackNode<type> *nTemp;    if(this->isReverse)    {        nTemp = this->top;        this->tail = this->top->previous;        this->top = this->tail;        free(nTemp);        nTemp = NULL;    }    else    {        nTemp = this->top;        this->head = this->top->next;        this->top = this->head;        free(nTemp);        nTemp = NULL;    }    this->len--;    return temp;}template <typename type>type Stack<type>::getTop(){if(len == -1 || this->top == NULL){return NULL;}return this->top->value;}template <typename type>bool Stack<type>::reverse(){    try{    if(this->len == -1)    {        return false;    }    if(this->isReverse)    {        this->top = this->head;        this->isReverse = false;    }    else    {        this->top = this->tail;        this->isReverse = true;    }    return true;    }catch(...){        return false;    }}template <typename type>bool Stack<type>::isReversed(){    return this->isReverse;}template <typename type>int Stack<type>::getLength(){    return this->len+1;}template <typename type>Stack<type>::~Stack(){    while(this->pop()) {}}#endif