item5.cpp

// empty.h
class Empty {
    // this class declares no members but still will implicitly have the 
    // below declared by the compiler (in the public scope)
    
    /*
    Empty(){...}                                // default constructor
    Empty(const Empty& rhs){...}                // copy constructor
    ~Empty(){...}                               // default destructor
    Empty& operator=(const Empty& rhs){...}     // copy assignment operator
    */
    
};

// main.cpp
int main(int argc, char * argv[]) {
    // code below is legal and will compile as constructors and methods 
    // used are implicitly declared by compiler
    Empty e1;
    Empty e2(e1);
    e1 = e2;
}