CS330 Spring 2004 Lecture 32

George Tzanetakis

Review for Final

Here are some questons. I will try to go over them in class.



1) Show the calling sequence of constructors/destructors when foo is called (for class A use A to signify the constructor and ~A the destructor)
for the following C++ code: 

class A 
{
    public: 
	A() { cout << "A" << endl;   } 
	~A() { cout << "~A" << endl; } 
}; 


class B
{
    private: 
	A a;
    public: 
	B() { cout << "B" << endl;} 
	~B(){ cout << "~B" << endl;}  
}; 

class C: public A 
{
     public : 
	C() { cout << "C" << endl;} 
	~C() { cout << "~C" << endl;} 
}; 


void foo() 
{ 
    A a;
    B b;
    C c; 
} 

...
....

...

foo(); 
...
...






2)  A CSC330 student emails you the following code complaining that it core dumps
when printRooms is called. What's wrong with the following code ? Explain in detail
and show how the problem can be solved:

class Game{
private:
     map<string, Room *> rooms;
....
....
};


void Game::addRoom(string name)
{
    Room newRoom(name);
    rooms[name] = &newroom;
}

void Game::printRooms()
{
    map<string, Room*>::iterator ri;
    for (ri = rooms.begin(); ri != rooms.end(); ++ri)
        cout << rooms->second << endl;
}




3) A print procedure is a good candidate for a dynamically bound method why ?



4) (Louden pg. 442-444) What will the output of main be for version 1 and version 2. 


class A 
{
   public: 
	void p() {cout << "A::p\n";} 
        virtual void q() { cout << "A::q\n";} 
	void f() 
	{
	     p();
	     q(); 
	} 
}; 


class B: public A 
{ 
   public: 
	void p() { cout << "B::p\n";} 
        void q() { cout << "B::q\n";} 
}; 


int main()     // version 1 
{ 
    A a; 
    B b; 
    a.f(); 
    b.f(); 
    a = b; 
    a.f(); 
} 


int main() // version 2 
{ 
   A* a = new A; 
   B* b = new B; 
   a->f(); 
   b->f(); 
   a = b; 
   a->f(); 
}