问题：设计字符串类， 支持下面的操作

MyString  s1; // 默认构造函数

MyString s2("hello"); // 含参构造函数

MyString  s3(s1); // 传参构造函数

MyString  s4(5, 'c'); // 自定义构造函数

= // 运算符重载

==    !=   >   <  // 运算符重载

---

代码：

#include <iostream>
#include <cstring>using namespace std;class Mystring{// <<friend ostream& operator<<(ostream &out,Mystring &s);// >>friend istream& operator>>(istream &in,Mystring &s);
private:char *m_space; // 存储数据size_t m_len; // 字符串长度
public:// 默认构造函数Mystring(){m_space = new char;strcpy(m_space,"");m_len = 0;}// 构造函数Mystring(const char *indata){m_len = strlen(indata);m_space = new char[m_len + 1];strcpy(m_space,indata);}// 拷贝构造函数(深拷贝)Mystring(const Mystring &s){m_len = s.m_len;m_space = new char[m_len + 1];strcpy(m_space,s.m_space);}// 析构函数~Mystring(){if(m_space != nullptr){delete [] m_space;m_space = nullptr;}}// 重载赋值运算符 =Mystring& operator=(const Mystring &s){if(m_space != nullptr){delete [] m_space;m_space = nullptr;}m_len = s.m_len;m_space = new char[m_len + 1];strcpy(m_space,s.m_space);return *this;}
};
// <<
ostream& operator<<(ostream &out,Mystring &s){out<<s.m_space;return  out;
}
istream& operator>>(istream &in,Mystring &s){// 对之前的内存进行管理(避免内存泄漏)if(s.m_space != nullptr){delete [] s.m_space;s.m_space = nullptr;}// 输入新的字符串char buf[1024];in>>buf;s.m_len = strlen(buf);s.m_space = new char[s.m_len + 1];strcpy(s.m_space,buf);return  in;
}
int main(){Mystring s1;Mystring s2("Hello");cout<<"Please input data:"<<endl;cin>>s2;s1 = s2;cout<<"s2: "<<s2<<endl;cout<<"s1: "<<s1<<endl;return 0;
}

输出：