C++学习笔记49:栈

栈是一种只能从一端访问的线性数据结构，栈是一种后进先出的数据结构

//stack.h
#ifndef STACK_H
#define STACK_H
#include <cassert>
template <class T, int SIZE = 50> class Stack
{
private:
    T list[SIZE];
    int top;
public:
    Stack();
    void push(const T &item);
    T pop();
    void clear();
    const T &peek() const;
    bool isEmpty() const;
    bool isFull() const;
};

//模板的实现
template <class T, int SIZE>
Stack<T, SIZE>::Stack():top(-1){}

template <class T, int SIZE> void Stack<T, SIZE>::push(const T &item)
{
    assert(!isFull());
    list[++top] = item;
}

template <class T, int SIZE> T Stack<T, SIZE>::pop() const
{
    assert(!isEmpty());
    return list[top--];
}

template <class T, int SIZE> const T &Stack<T, SIZE>::peek() const
{
    assert(!isEmpty());
    return list[top];
}

template <class T, int SIZE> bool Stack<T, SIZE>::isEmpty() const
{
    return top == -1;
}

template <class T, int SIZE> bool Stack<T, SIZE>::isFull() const
{
    return top == SIZE - 1;
}

template <class T, int SIZE> void Stack<T, SIZE>::clear()
{
    top = -1;
}

#endif // 

 栈的引用：判断是否存在不匹配的（）

#include <iostream>
#include <string>
#include <cassert>
using namespace std;

template <class T, int MAX = 1000> class Stack
{
private:
    T list[MAX + 1];
    int top;
public:
    Stack();
    void push(const T &item);
    T pop();
    const T & peek() const;
    bool isEmpty() const;
};


template <class T, int MAX> Stack<T, MAX>::Stack() :top(-1)
{

}

template <class T, int MAX> void Stack<T, MAX>::push(const T &item)
{
    if (top != MAX - 1)
    {
        list[++top] = item;
    }
}

template <class T, int MAX> bool Stack<T, MAX>::isEmpty() const
{
    return top == -1;
}

template <class T, int MAX> T Stack<T, MAX>::pop()
{
    assert(!isEmpty());
    return list[top--];
}

template <class T, int MAX> const T &Stack<T, MAX>::peek() const
{
    assert(!isEmpty());
    return list[top];
}

void judgeBrackets(string str)
{
    Stack<char>p;
    int k = 0;
    int count = 0;
    while (str[k] != '\0')
    {
        if (str[k] == '(')
        {
            p.push(str[k]);
            count++;
        }
        if (str[k] == ')')
        {
            if (count == 0)
            {
                cout << "NO" << endl;
                count--;
                break;
            }
            else
            {
                p.pop();
                count--;
            }
        }
        k++;
    }
    if (count == 0)
        cout << "Yes" << endl;
    if (count > 0)
        cout << "NO" << endl;
}

int main()
{
    string str;
    while (cin >> str)
    {
        judgeBrackets(str);
    }
}