pure virtual function implemented without error

[leonid1990]

Hello, I created an abstract class with pure virtual function. If I understand correctly, there is no way to call/implement such function.
nevertheless, just out of curiosity I tried to implement it and everything compiled without any errors or warnings (I use VS 2012).
Why?

[Peter87]

It is possible. Making the function pure virtual just makes the class abstract, and all derived non-abstract classes are forced to override the function.

[leonid1990]

ok, thanks man

[numbergamer]

It is possible to implement a pure virtual function. It might come handy when you have the same implementation for a function for all the derived classes.

for eg:

class A {
public:
virtual void foo() = 0;
}

void A::foo() { cout << "Pure" << endl; }

class B : public A{
public:
void foo() { A::foo(); }
}

class C : public A{
public:
void foo() { A::foo(); }
}

I have heard that you can also implement the function along with the pure specifier in Microsoft Visual C++. i.e.,

class A {
public:
void foo() { cout << "pure" << endl; } = 0
}

is valid in MS Visual C++.

But this is an error in other compilers and its better if you don't use it.