++ Operators: Prefix & Postfix
	string & list::operator ++ () {  //prefix   if (!ptr || !(ptr->next)) {   //consider what other alternatives there are     string * temp = new string; //just in case     return *temp;   }   ptr = ptr->next;   return ptr->obj; } string operator ++ (int){  //postfix   string temp;   if (!ptr) {     temp = “\0”;    //what does this do?     return temp;    //and this?   }   temp = ptr->obj;  //and this?   ptr = ptr->next;  //and this?   return temp;      //and this? }