#pragma once

#include <iostream>

using namespace std;

class MyString

{

public:

    MyString();

    MyString(const char *p);

    MyString(const MyString& s);

    ~MyString();

public:

    MyString& operator=(const char* p);

    MyString& operator=(const MyString &s);

    char& operator[](int index);

    // 重载左移操作符、右移操作符，注意区别

    friend ostream& operator<<(ostream &out, MyString &s);

    friend istream& operator>>(istream &in, MyString &s);

    //重载双等号和不等号

    bool operator==(const char* p);

    bool operator!=(const char* p);

    bool operator==(const MyString& s );

    bool operator!=(const MyString& s);

    //重载大于和小于操作符

    int operator<(const char* p);

    int operator>(const char* p);

    int operator<(const MyString &s);

    int operator>(const MyString &s);

    // 把类的指针 单独使用,通过 s1.c_str() 来调用

    char *c_str()

    {

        return m_p;

    }

private:

    int m_len;

    char *m_p;

};

#define  _CRT_SECURE_NO_WARNINGS

#include "MyString.h"

MyString::MyString()

{

    m_len = ;

    m_p = new char[m_len + ];

    strcpy(m_p, "");

}

MyString::MyString(const char *p)

{

    if (p == NULL)

    {

        m_len = ;

        m_p = new char[m_len + ];

        strcpy(m_p, "");

    }

    else

    {

        m_len = strlen(p);

        m_p = new char[m_len + ];

        strcpy(m_p, p);

    }

}

//MyString s3 = s2;

MyString::MyString(const MyString& s)

{

    m_len = s.m_len;

    m_p = new char[m_len + ];

    strcpy(m_p, s.m_p);

}

MyString::~MyString()

{

    if (m_p != NULL)

    {

        delete[]m_p;

        m_p = NULL;

        m_len = ;

    }

}

MyString& MyString::operator=(const char* p)

{

    if (m_p != nullptr)//释放旧的内存

    {

        delete[] m_p;

        m_len = ;

    }

    if (p == NULL) //根据p分配新的内存

    {

        m_len = ;

        m_p = new char[m_len + ];

        strcpy(m_p, "");

    }

    else

    {

        m_len = strlen(p);

        m_p = new char[m_len + ];

        strcpy(m_p, p);

    }

    return *this;

}

MyString& MyString::operator=(const MyString &s)

{

    if (m_p != nullptr)//释放旧的内存

    {

        delete[] m_p;

        m_len = ;

    }

    m_len = strlen(s.m_p);

    m_p = new char[s.m_len + ];

    strcpy(m_p, s.m_p);

    return *this;

}

char& MyString::operator[](int index)

{

    return m_p[index];

}

ostream& operator<<(ostream &out, MyString &s)

{

    out << s.m_p;

    return out;

}

istream& operator>>(istream &in, MyString &s) {

    cin >> s.m_p;

    return in;

}

bool MyString::operator==(const char* p)

{

    if (p == nullptr)

    {

        if (m_len != )

        {

            return false;

        }

        else

            return true;

    }

    else

    {

        if (m_len == strlen(p))

        {

            return !strcmp(m_p, p);

        }

        else

            return false;

    }

}

bool MyString::operator!=(const char *p)

{

    return !(*this == p);

}

bool MyString::operator==(const MyString& s)

{

    if (m_len != s.m_len)

        return false;

    return strcmp(m_p,s.m_p);

}

bool MyString::operator!=(const MyString& s)

{

    return !(*this == s);

}

//if(s3<"bb"")

int MyString::operator<(const char* p){

    return strcmp(m_p, p);

}

int MyString::operator>(const char* p) {

    return strcmp(p, m_p);

}

int MyString::operator<(const MyString &s) {

    return strcmp(m_p, s.m_p);

}

int MyString::operator>(const MyString &s) {

    return strcmp(s.m_p, m_p);

}

#include <iostream>

using namespace std;

#include "MyString.h"

//void main01()

//{

//    MyString s1;

//    MyString s2("s2");

//    MyString s2_2 = NULL;

//    MyString s3 = s2;

//

//    MyString s4 = "s4";

//    s4 = s2;

//    s4[1] = '9';

//    cout << s4[1] << endl;

//    cout << s4 << endl;//左移操作符的重载

//

//    system("pause");

//}

void main()

{

    MyString s1;

    MyString s2("s2");

    MyString s3 = NULL;

    cout << (s2 > "s") << endl;

    cin >> s2;

    cout << s2 << endl;

    system("pause");

}