C++中的模拟class string类的代码 cpp

//一个C++初学者的string类，恳请朋友们多多指点 //特殊功能：- 取负数运算符代表将字符串翻转 函数头： class string{ friend int len(string &); friend const string & operator+(const string &s1,const string &s2); friend std::ostream & operator<<(std::ostream &theStream,const string & str); friend const string & operator+(const string &s1,const char * s2); friend const string & operator+(const char * s2,const string &s1); private: int itslen; public: string(); string(int length); string(string & str); string(const char *str); const string & operator=(const char str[]); const string & operator+=(const char str[]); const string & operator-()const; const char & operator[](int index) const; operator char*() const; char & operator[](const int index); ~string(); void put(); char *inner; operator int()const; };