C++-3

定义一个Person类，有const修饰的成员name；int成员age，char类型的成员sex，定义一个Stu类，包含Person 成员，double *成员，要求：写出Person和Stu的构造和析构函数，每个类至少写出两种构造函数，实现一个公有的show函数，输出Stu类中属性和Person类中属性的值。在上一个练习的基础上，写出Person类和Stu类的拷贝构造函数。完成拷贝赋值函数

#include <iostream>
using namespace std;
class Person
{
    const string name;
    int age;
    char sex;
public:
    Person():name("zhangsan")
    {}
    Person(string name,int age,char sex):name(name),age(age),sex(sex)
    {}
    ~Person()
    {}
    void show()
    {
        cout << name << endl;
        cout << age << endl;
        cout << sex << endl;
    }
    Person(const Person &other):name(other.name),age(other.age),sex(other.sex)
    {}
    Person &operator=(const Person &other)
    {
        if(&other != this)
        {
            this->age = other.age;
            this->sex = other.sex;
        }
    }

};
class Stu
{
    Person p1;
    double *pd;
public:
    Stu():pd(new double)
    {}
     Stu(string name,int age,char sex,double score):p1(name,age,sex),pd(new double(score))
    {}
    ~Stu()
    {
        cout << "z准备释放空间:" << pd << endl;
        delete pd;
        cout << "Stu的析构函数" << endl;
    }
    void show()
    {
        p1.show();  //通过Person类型的p1成员，调用Person中的show函数
        cout << "Stu中的show:" << *pd << endl;
    }
    //实现Stu的拷贝构造，调用其他类的拷贝构造函数时，也需要传同类引用
    Stu(const Stu &other):pd(new double(*(other.pd))),p1(other.p1)
    {}
    Stu &operator=(const Stu &other)
    {
        if(&other != this)
        {
            *(this->pd) = *(other.pd);
            this->p1 = other.p1;
        }
    }
};
int main()
{
    Stu s2("zhangsan",20,'m',23.9);
    s2.show();
    Stu s3 ;
    s3 = s2;
    s3.show();
    return 0;
}

#include <iostream>
#include <cstring>
using namespace std;
class myString
{
    private:
        char *str;          //记录c风格的字符串
        int size;            //记录字符串的实际长度
    public:
        //无参构造
        myString():str(new char [64]())
        {}
        //有参构造
        myString(char *str):str(new char [64]())
        {
            strcpy(this->str,str);
            size=mysize();
        }
        //拷贝构造
        myString(const myString &other):str(new char [64]()),size(other.size)
        {
            strcpy(this->str,other.str);
        }
        //拷贝赋值函数
        myString &operator=(const myString &other)
        {
            if(&other != this)
            {
                this->size = other.size;
                strcpy(this->str,other.str);
            }
            return *this;
        }
        //析构函数

        ~myString()
        {
            delete [] str;
        }
        //判空函数
        int empty()
        {
            if(str==nullptr&&size==0)
            {
                return 1;
            }
            return 0;
        }
        //size函数
        int mysize()
        {   int i=0;
            for( i=0;str[i]!='\0';i++);

            return i;
        }
        //c_str函数
        char* c_str()
        {
            return  str;
        }
        //at函数

        char &at(int pos)
        {
            if(pos<mysize()&&pos>=0)
            {
                int i=0;
               
                return str[pos];

            }
            cout << "pos参数错误没有该值" << endl;
        };

};
int main()
{
    myString s1("hello");
    cout << "empty " << s1.empty() << endl;
    cout << "at    " << s1.at(1) << endl;
    cout << "at    " << s1.at(4) << endl;
    cout << "size  " << s1.mysize() << endl;
    cout << "c_str " << s1.c_str() << endl;
    myString s2 = s1;
    cout << "copy构造" << s2.c_str() << endl;
    myString s3;
    s3 = s1;
    cout << "copy赋值"<< s3.c_str() << endl;

    return 0;
}