链栈的初始化

来源：互联网发布：淘宝网系统架构分析编辑：程序博客网时间：2024/05/21 07:30
#include <iostream>#include <assert.h>using namespace std;template <class T>class LinkedStack;                                          //类声明template <class T>                                          //全局的operator<<、>>函数都要在类定义前声明istream& operator>>(istream &is,LinkedStack<T> &s);template <class T>ostream& operator<<(ostream &os,LinkedStack<T> &s);template <class T>struct Node{    T data;    Node<T> *next;};template <class T>class LinkedStack{public:    LinkedStack();                            //初始化栈，链表头结点为top栈顶位置    ~LinkedStack(){makeEmpty();cout<<"析构函数执行"<<endl;}                        //析构函数，置空栈    void Push(const T&x);    T Pop();    T getTop();    bool IsEmpty()const{return (top->next==NULL)?true:false;}    int getSize()const;    void makeEmpty();    friend istream& operator>> <>(istream &is,LinkedStack<T> &s);                  //模板函数做友元要显式的声明模板形参,                                                                                   //如果<>内空就是把当前类的模板参数传进来用.    friend ostream& operator<< <>(ostream &os,LinkedStack<T> &s);                 //<>不能省略private:    Node<T> *top;                                         //栈顶指针};template <class T>istream& operator>>(istream &is,LinkedStack<T> &s){    int n,i,m;    cout<<"输入要创建的栈的元素个数:";    is>>n;    cout<<endl;    cout<<"输入栈中元素:";    for(i=0;i<n;i++)    {        is>>m;        s.Push(m);    }    return is;}template <class T>ostream& operator<<(ostream &os,LinkedStack<T> &s)                    //重载<<运算符{    os<<"栈中元素个数为："<<s.getSize()<<endl;    Node<T> *p=s.top->next;    int i=0;    while(p)    {os<<++i<<":"<<p->data<<endl;    p=p->next;    }    return os;}int main(){    LinkedStack<int> s;    cin>>s;    cout<<"输出创建的栈：";    cout<<s;    cout<<"此时栈顶元素为:"<<s.getTop()<<endl<<endl;    s.Push(s.getSize());    cout<<"压入栈长到栈中:"<<endl;    cout<<"此时栈顶元素为:"<<s.getTop()<<endl;    cout<<"出三次栈并依次输出栈顶元素"<<s.Pop();    cout<<" "<<s.Pop()<<" ";    cout<<s.Pop()<<endl;    //不能写成cout<<s.Pop<<" "<<s.Pop()<<" "<<s.Pop()<<endl;  否则输出顺序恰好相反    //cout<<"输出现在的栈："<<s;    s.makeEmpty();    cout<<"置空栈后栈的长度:"<<s.getSize()<<endl;    return 0;}template <class T>LinkedStack<T>::LinkedStack()            //初始化栈{    cout<<"构造函数执行"<<endl;    top=new Node<T>;                    //创建头结点，返回给top指针    top->next=NULL;}template <class T>void LinkedStack<T>::Push(const T&x)            //插入元素，插在头结点*top与开始结点之间{    Node<T> *s;    s=new Node<T>;    s->data=x;    s->next=top->next;    top->next=s;    return ;}template <class T>T LinkedStack<T>::Pop()                         //退栈并得到栈顶元素{    T x;    assert(top->next!=NULL);    Node<T> *p;    p=top->next;    top->next=p->next;    x=p->data;    delete p;    return x;}template <class T>T LinkedStack<T>::getTop()                       //得到栈顶元素{    T x;    assert(top->next!=NULL);    x=top->next->data;    return x;}template <class T>int LinkedStack<T>::getSize()const                       //得到链式栈的长度{    int n=0;    if(top->next==NULL) return 0;    Node<T> *p=top->next;    while(p)    {        n++;        p=p->next;    }    return n;}template <class T>void LinkedStack<T>::makeEmpty(){    if(top->next==NULL) return ;    Node<T> *p=top->next,*q=p->next;    while(1)    {        delete p;        p=q;        if(p==NULL) break;        q=q->next;    }    top->next=NULL;    return ;}
0 0