#include <iostream>
#include <iomanip>
using namespace std;
class Person{
    const string name;
    int age;
    char sex;
public:
    Person(const string name):name(name){
        cout << "第一个Person构造函数" << endl;
    }
    Person():name("zhangsan"){
        cout << "第二个Person构造函数" << endl;
    }
    ~Person(){
        cout << "Person的析构函数" << endl;
    }
    void show(){
        cout << "name:" << name << endl << "age:" << age << endl << "sex:" << sex << endl;
    }
    void set(int age,char sex){
        this->age=age;
        this->sex=sex;
    }
    Person(const Person &other):name(other.name){

        this->age = other.age;
        this->sex = other.sex;
        cout << "Person的拷贝构造函数" << endl;
    }
    Person &operator=(const Person &other){
        //this->name=other.name;
        this->age=other.age;
        this->sex=other.sex;
        cout << "Person的拷贝赋值函数" << endl;
        return* this;
    }
};
class Stu{
    Person p1;
    double* score;
public:
    Stu():score(new double){
        cout << "这是第一个Stu构造函数" << endl;
    }
    Stu(const string name):p1(name),score(new double){
        cout << "这是第二个Stu构造函数" << endl;
    }
    ~Stu(){
        delete score;
        cout << "Stu的析构函数" << endl;
    }
    void show(){
        p1.show();
        cout << "score:" << score << endl;
    }
    void set(int age,char sex,double score){
        p1.set(age,sex);
        *(this->score)=score;
    }
    Stu(const Stu &other):p1(other.p1),score(new double(*(other.score))){  //初始化的顺序很重要，否则会报一个警告

        cout << "Stu的拷贝构造函数" << endl;
    }
    Stu &operator=(const Stu &other){
        *(this->score)=*(other.score);
        cout << "Stu的拷贝赋值函数" <<endl;
        return* this;
    }
};

int main()
{

    Stu s1("王华");
    s1.set(18,'m',70);
    s1.show();
    Stu s2=s1;
    s2.show();
    return 0;
}

#include <iostream>
#include <iomanip>
#include <cstring>
using namespace std;
class myString{
private:
    char* str;
    int size;
public:
    myString():str(new char[120]){
        cout << "无参构造函数" << endl;
    }
    myString(char* str):str(new char[120]){
        this->str=str;
        this->size=strlen(str);
        cout << "有参构造函数" << endl;
    }
    myString(const myString &other):str(new char[120]){
        this->str=other.str;
        cout << "拷贝构造函数" << endl;
    }
    myString &operator=(const myString &other){
        this->str=other.str;
        this->size=other.size;
        cout << "拷贝赋值函数" << endl;
        return* this;
    }
    ~myString(){
        delete[] str;

        cout << "析构函数" << endl;
    }
    int empty(){
        cout << "判空函数" << endl;
        if(strlen(this->str)==0){
            return 1;
        }
        else return 0;
    }
    int mysize(){
        return strlen(this->str);
    }
    const char* c_str(){
        return this->str;
    }
    char& at(int pos){
        if(size>=pos){
            return str[pos];
        }else{
            cout << "error ,out " << endl;

        }
    }
};

int main()
{
    char s[20]="hello world";
    myString s1(s);
    myString s2;
    s2=s1;
    cout << s1.at(10) << endl;
    cout << s2.c_str() << endl;

    return 0;
}