In Inheritance: Can I override base class data members?

Question

Let's say I have two classes like the following:

Class A
{
public:
..
private:
  int length;
}

Class B: public Class A
{
public:
..
private:
 float length;
}

What I would like to know is:

1. Is overriding of base class data members allowed?
2. If yes, is it a good practice?
3. If no, what is the best way to extend the type of the data members of a class?

There is a class that satisfies my needs and I want to reuse it. However for my program needs, its data members should be of another type.

I have some books, but all of them refer only to overriding of base class member methods.

Answer 1

You can use templatized members i.e., generic members instead of overriding the members.

You can also declare a VARIANT(COM) like union.

   struct MyData
   {
        int vt;              // To store the type

        union 
        {                
            LONG      lVal;
            BYTE      bVal;
            SHORT     iVal;
            FLOAT     fltVal;
            .
            .
        }
   };