Inherit from const class

Question

I would like to inherit from a class with the const specifier like this:

class Property
{
    int get() const;
    void set(int a);
};

class Co         


        

Answer 1

If you create a const member function set, you will get what you need.

class Property
{
    int get() const;
    void set(int a);
};

class ConstChild : public Property
{
    void set(int a) const {}
};

The only caveat is that a sly user can circumvent your intention by using:

ConstChild child;
child.set(10);    // Not OK by the compiler

Property& base = child;
base.set(10);    // OK by the compiler