《C++实现数据结构》：堆栈

堆栈是限定插入和删除操作都在表的同一端进行的线性表，是后进先出（LIFO）的线性数据结构。

#include <iostream>using namespace std;//堆栈基类template <typename T>class Stack{public:    virtual bool IsEmpty() const = 0;   //若栈空,则返回true    virtual bool IsFull() const = 0;    //若栈满,则返回true    virtual bool Top(T &x) const = 0;   //在x中返回栈顶元,若操作成功,则返回true    virtual bool Push(T x) = 0;         //在栈顶插入元素x(入栈),若操作成功,则返回true    virtual bool Pop() = 0;             //从栈中删除栈顶元素(出栈),若操作成功,则返回true    virtual void Clear() = 0;           //清除栈中全部元素};

一、堆栈的顺序表示
和线性表的顺序表示一样，是用数组来构造的。

//堆栈的顺序表示template <typename T>class SeqStack:public Stack<T>{private:    int top;        //栈顶指针    int maxTop;     //最大栈顶指针    T* s;public:    SeqStack(int mSize);    ~SeqStack();    bool IsEmpty() const;   //若栈空,则返回true    bool IsFull() const;    //若栈满,则返回true    bool Top(T &x) const;   //在x中返回栈顶元,若操作成功,则返回true    bool Push(T x);         //在栈顶插入元素x(入栈),若操作成功,则返回true    bool Pop();             //从栈中删除栈顶元素(出栈),若操作成功,则返回true    void Clear();           //清除栈中全部元素};template <typename T>SeqStack<T>::SeqStack(int mSize) {    maxTop = mSize - 1;    s = new T[mSize];    top = -1;}template <typename T>SeqStack<T>::~SeqStack() {    delete[] s;}template <typename T>bool SeqStack<T>::IsEmpty() const {    return -1 == top;}template <typename T>bool SeqStack<T>::IsFull() const {    return top == maxTop;}template <typename T>bool SeqStack<T>::Top(T &x) const {    if (IsEmpty()) {        cout<<"Empty"<<endl;        return false;    }    x= s[top];    return true;}template <typename T>bool SeqStack<T>::Push(T x) {    if (IsFull()) {        cout << "Full" << endl;        return false;    }    s[++top] = x;    return true;}template <typename T>bool SeqStack<T>::Pop() {    if (IsEmpty()) {        cout<<"Empty"<<endl;        return false;    }    top--;    return true;}template <typename T>void SeqStack<T>::Clear() {    top = -1;}

二、堆栈的链接表示
表头指针的next永远指向栈顶。

//堆栈的链接表示template <typename T>class SingleStack;template <typename T>class Node{private:    T element;    Node<T>* next;    friend class SingleStack<T>;};template <typename T>class SingleStack:public Stack<T>{private:    Node<T>* head;    bool IsFull() const{};public:    SingleStack();    ~SingleStack();    bool IsEmpty() const;   //若栈空,则返回true    bool Top(T &x) const;   //在x中返回栈顶元,若操作成功,则返回true    bool Push(T x);         //在栈顶插入元素x(入栈),若操作成功,则返回true    bool Pop();             //从栈中删除栈顶元素(出栈),若操作成功,则返回true    void Clear();           //清除栈中全部元素};template <typename T>SingleStack<T>::SingleStack() {    head = new Node<T>;    head->next = NULL;}template <typename T>SingleStack<T>::~SingleStack() {    Node<T> *p;    while (head != NULL) {        p = head;        head = head->next;        delete (p);    }}template <typename T>bool SingleStack<T>::IsEmpty() const {    if (head->next == NULL) {        return true;    } else {        return false;    }}template <typename T>bool SingleStack<T>::Top(T &x) const {    if (IsEmpty()) {        cout<<"Empty"<<endl;        return false;    }    x = head->next->element;    return true;}template <typename T>bool SingleStack<T>::Push(T x) {    Node<T>* newNode = new Node<T>;    newNode->element = x;    newNode->next = head->next;    head->next = newNode;}template <typename T>bool SingleStack<T>::Pop() {    if (IsEmpty()) {        cout<<"Empty"<<endl;        return false;    }    Node<T>* p = head->next;    head->next = p->next;    delete (p);}template <typename T>void SingleStack<T>::Clear() {    Node<T> *p = head->next;    head->next = NULL;    Node<T> *q;    while (p != NULL) {        q = p;        p = p->next;        delete (q);    }}

最后的测试用例：

int main() {    int n = 10;    Stack<int> *stack = new SeqStack<int>(10);    //Stack<int> *stack = new SingleStack<int>();    for (int i = 0; i < 5; ++i) {        stack->Push(i);    }    int x;    if (stack->Top(x)) {        cout<<"top:"<<x<<endl;    }    stack->Pop();    if (stack->Top(x)) {        cout<<"now top:"<<x<<endl;    }    return 0;}