派生类的成员函数

Question

When a class is derived from a base class, will the member functions of the base class become member function of the derived class. That is, for example if I write:

class A 
{ 
public : void f();
};
class B : public A 
{ 
public : void f1();
};

Now if the question is to name the member functions in class B, then will f() also become a member function of class B ?

Answer 1

Yes, class B has two functions: f1() and f() .

If f() was protected in A , too, but f() could only be used from within the member functions of A and B (and from friend s).

And if f() was private , B would have only one function f1() .

Answer 2

class A { 
public : void f();
};
class B : public A 
{ 
public : void f1();
};

Now code is valid. It is visible. Even when you change f1 name to f it is still visible in B class. If you wanna use it use scope operator ::.

Like this:

A::f()

More about basic inheritence http://www.learncpp.com/cpp-tutorial/112-basic-inheritance-in-c/

Answer 3

then will f() also become a member function of class B ?

No. f() is still a member function of class A , class B just inherits it. In your case it's a public member function and public inherit, means you can call f() on a B object.

B b;
b.f();

On the other hand, class B can define own member function f() :

class A 
{ 
public : void f();
};
class B : public A 
{ 
public : void f(); // will hide A::f()
};