How can I create an abstract base class in C++?

Question

How would I go about doing the following in C++ (the following code is C#):

class Base
{
    public virtual void Foo()
    {
        // do stuff...
    }
}

class C : Base
{
    public override void Foo()
    {
        base.Foo(); // <=== how do you do this line?
    }
}

Answer 1

Use operator :::

class Base
{
public:
    virtual ~Base() {}
    virtual void Foo()
    {
        // do stuff
    }
};

class C : public Base
{
public:
    void Foo()
    {
        Base::Foo();
    }
};

To have an abstract class in C++ at least one method needs to be pure virtual:

class Base
{
public:
    virtual ~Base() {}
    virtual void Foo() {}
    virtual void another_function() = 0; // Pure virtual function.
};