C++day4

#include <iostream>
#include <cstring>
using namespace std;

class myString
{
private:
    char *str;
    int size;
public:
    // 无参构造
       myString() : str(new char), size(0) {}

       // 有参构造
       myString(const char *other)
       {
           size = strlen(other);
           str = new char[size + 1];
           strcpy(str, other);
       }
       myString (string s1,int size):str(new char [size+1],size(size+1)
       {
           strcpy(str,s1.c_str());
           cout<<"myString的有参构造函数"<<endl;
       }
       // 拷贝构造
       myString(const myString &other) : size(other.size)
       {
           str = new char[size + 1];
           strcpy(str, other.str);
       }
       // 拷贝赋值函数
       myString& operator=(const myString &other)
       {
           if (this != &other)
           {
               size = other.size;
               str = new char[size + 1];
               strcpy(str, other.str);
           }
           return *this;
       }

       // 析构函数
       ~myString()
       {
           delete []str;
       }

       // 判空函数
       bool isempty() const
       {
           return size == 0;
       }
       //size函数
       int len()
       {
           return size;
       }
       //c_str函数
       char *c_str()
       {
           return str;
       }
       //at函数
       char*at(int pos)
       {
           if(pos<0||pos>=size)
           {
               return *（str）;
           }
           return *(str+pos);
       }
       void operator+(Mystring &s1){
             char *temp=new char[size];
             strcpy(temp,str);
             size=size+s1.size;
             delete [] str;
             str=new char[size];
             strcpy(str,temp);
             strcat(str,s1.c_str());
         }
         //关系运算符
         bool operator>(const Mystring s1)const{
             for(int i=0;i<size;i++){
                 if(*(str+i)!=*(s1.str+i)){
                     return *(str+i)>*(s1.str+i);
                 }
             }
             return 0;
         }
         bool operator<(const Mystring s1)const
         {
             for(int i=0;i<size;i++)
             {
                 if(*(str+i)!=*(s1.str+i))
                 {
                     return *(str+i)<*(s1.str+i);
                 }
             }
             return 1;
         }
     ostream &operator<<(ostream &cout,myString s1)
     {
         cout<<s1.c_str()<<endl;
         return cout;
     }
     istream &operator>>(istream &cin,myString &s1)
     {
         if(s1.str!=nullptr){
             delete [] s1.str;
         }
         string s;
         cin>>s;
         s1.size=strlen(s.c_str());
         s1.str=new char[s1.size+1];
         strcpy(s1.str,s.c_str());
         return cin;
};
int main()
{
    myString s1("hello");
    myString s2("hhello");
    cout<<(s1<s2)<<endl;
    cout<<(s1>s2)<<endl;
    return 0;
}