Exam 15: Polymorphism and Virtual Functions

If the override specifier is added to the end of a member function declaration,what happens if the function is not specified as virtual in the parent class?

The virtual function mechanism binds the "right" function to objects.

It is useful to define a class for which no objects may be defined.

Why do you not get an undefined reference in virtual table error when you don't define a pure virtual function?

Explain the difference between virtual functions,late binding,and polymorphism.

Virtual functions allow old code to call new code.

Is there an error? class B { public: void virtual f(); }; void B::f(){/*...*/}

This is legal code. class B { public: // ... virtual void f()= 0; }; int main(){ B b1,b2;/*...*/ }

In C++,a virtual destructor is invoked whenever a virtual constructor was used to create the object.

Give some simple recommendation for when a destructor should be declared virtual.

Destructors are automatically virtual.

What is the error? class B { public: virtual void f(); }; virtual void B::f(){/*...*/}

The base class destructor must be virtual.

In a class,functions declared with the virtual keyword need not be defined.