class R;forward reference
class A {\fbox{A}
public: A(int n);integer elements
A(char* s);elements
~A() { delete rep; } R* operator->() { return rep; } private: R* rep; };
class R;forward reference
class A {\fbox{A}
public: A(int n);integer elements
A(char* s);elements
~A() { delete rep; } R* operator->() { return rep; } private: R* rep; };