string - C++ Overloading [] from left and right -

i'm trying think how can overload [] both left , right function set , custom string class i'm working on. example:

char x= objar[1]; //get objar[2]='a'; //set 

the string class looks this:

class string { private:     char* data;     unsigned int datasize; public:     string();     string(char);     string(char*);     string(string&);     ~string();     char* getdata();     int getsize(); }; 

if have data up, can return reference:

char& string::operator[] (size_t idx) { return data[idx]; }  char string::operator[] (size_t idx) const { return data[idx]; } 

in case, should sufficient. however, if not option whatever reason (e.g. if data not of proper type), return proxy object:

class string {   void setchar(size_t idx, char c);   char getchar(size_t idx);    class charproxy   {     size_t idx;     string *str;   public:     operator char() const { return str->getchar(idx); }     void operator= (char c) { str->setchar(idx, c); }   };  public:   charproxy operator[] (size_t idx)   { return charproxy{idx, this}; }    const charproxy operator[] (size_t idx) const   { return charproxy{idx, this}; } }; 

this enable things implicit data sharing copy-on-write.