栈

#pragma once
class MyStack
{
public:
    MyStack(int size);               //分配内存初始化栈空间，设定栈容量，栈顶
    ~MyStack();                      //回收栈空间内存
    bool stackEmpty();              //判定栈是否为空，为空返回true，非空返回false
    bool stackFull();               //判定栈是否已满，为满返回true，不满返回false
    void clearStack();              //清空栈
    int stackLength();               //已有元素的个数
    bool push(char elem);           //元素入栈，栈顶上升
    bool pop(char &elem);          //元素出栈，栈顶下降
    void stackTraverse(bool isFromButtom);       //遍历栈中所有元素

private:
    char *m_pBuffer;        //栈空间指针
    int m_iSize;            //栈容量
    int m_iTop;             //栈顶，栈中元素个数
};

#include <iostream>
#include "MyStack.h"
using namespace std;


//分配内存初始化栈空间，设定栈容量，栈顶
MyStack::MyStack(int size)
{
    
    m_iSize = size;                 //栈容量
    m_pBuffer = new char[m_iSize];  //动态申请内存
    m_iTop = 0;                     //栈顶置为0
}

MyStack::~MyStack()
{
    delete[]m_pBuffer;   //释放内存
}

//判定栈是否为空，为空返回true，非空返回false
bool MyStack::stackEmpty()
{
    //写成这种形式可以防止代码写成=，写成=会报错
    if (0 == m_iTop) //if(m_iTop == 0)
    {
        return true;
    }
    return false;
}


//判定栈是否已满，为满返回true，不满返回false
bool MyStack::stackFull()
{
    if (m_iTop == m_iSize)  
    {
        return true;
    }
    return false;
}

//清空栈
void MyStack::clearStack()
{
    m_iTop = 0;
}

//已有元素的个数
int MyStack::stackLength()
{
    return m_iTop;
}

//元素入栈，栈顶上升
bool MyStack::push(char elem)
{
    //满了直接返回
    if (stackFull())
    {
        return false;
    }
    //入栈
    m_pBuffer[m_iTop] = elem;
    //栈顶++
    m_iTop++;
    return true;
}
/*
char MyStack::pop()
{
    if(stackEmpty())
    {
        throw 1;
    }
    else
    {
        m_iTop--;
        return m_pBuffer[m_iTop];
    }
}
*/

//元素出栈，栈顶下降
bool MyStack::pop(char &elem)
{
    //判断栈是否空，空直接返回
    if (stackEmpty())
    {
        return false;
    }
    //栈顶--(注意入栈的时候栈顶++指向的是一个空位置，故先--)
    m_iTop--;

    //直接取出
    elem = m_pBuffer[m_iTop];
    return true;
}


//遍历栈中所有元素
void MyStack::stackTraverse(bool isFromButtom)
{
    if (isFromButtom)
    {
        //从栈底向栈顶遍历
        for (int i = 0; i < m_iTop; i++)
        {
            cout << m_pBuffer[i] << ",";
        }
    }
    else
    {
        //从栈顶向栈底遍历，同样因为入栈时栈顶++，故栈顶-1的位置才实际有值
        for (int i = m_iTop - 1; i >= 0; i--)
        {
            cout << m_pBuffer[i] << ",";
        }
    }
}

#include <iostream>
#include "stdlib.h"
#include "MyStack.h"
using namespace std;


int main(void)
{
    MyStack *pStack = new MyStack(5);

    pStack->push('h');  //底
    pStack->push('e');
    pStack->push('l');
    pStack->push('l');
    pStack->push('o'); //顶

    //遍历（栈底到栈顶）
    pStack->stackTraverse(true);

    char elem = 0;

    //出栈
    pStack->pop(elem);

    cout << endl;
    cout << elem << endl;

    //pStack->clearStack();

    //遍历（栈顶到栈底）
    pStack->stackTraverse(false);

    //输出栈内元素个数
    cout << pStack->stackLength() << endl;


    if (pStack->stackEmpty())
    {
        cout << "栈为空" << endl;
    }

    if (pStack->stackFull())
    {
        cout << "栈为满" << endl;
    }

    delete pStack;
    pStack = NULL;

    system("pause");
    return 0;
}