1、完成下面类

#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():size(10)
    {
        str = new char[size];         //构造出一个长度为10的字符串
        strcpy(str,"");
        cout << "myString的无参构造" << endl;
    }
    //有参构造
    myString(const char *s)
    {
        size = strlen(s);
        str = new char[size+1];
        strcpy(str,s);
        cout << "myString的有参构造" << endl;
    }
    //拷贝构造
    myString(const myString &other):str(new char(*(other.str))),size(other.size)
    {
        cout << "myString的拷贝构造函数" << endl;
    }
    //析构函数
    ~myString()
    {
        delete str;
        str = nullptr;
    }
    //判空函数
    int myempty()
    {
        if(size == 0)
        {
            cout << "为空" << endl;
        }
        return size==0;
    }
    //size函数
    int mysize()
    {
        return size;
    }
    //c_str函数
    char *myc_str()
    {
        str[size+1] = '\0';
        return str;
    }
    //at函数
    char &at(int pos)
    {
        if(pos >= 0 && pos < size)
        {
            return str[pos];
        }
        else
        {
            cout << "越界" << endl;
            return str[0];
        }
    }
    void show()
    {
        cout << "str = " << str << endl;
        cout << "size = " << size << endl;
    }
};

int main()
{
    myString s1;
    s1.show();
    myString s2("Hello World");
    s2.show();
    myString s3(s2);
    return 0;
}