Question

Consider the following classes:

class Box

{

    private bool isLidOpen;

    public Box()

    {

        isLidOpen = true;

    }

    public virtual void OpenLid()

    {

        isLidOpen = true;

    }

    public virtual void CloseLid()

    {

        isLidOpen = false;

    }

}

class LockableBox : Box

{

    private bool isLidLocked;

    public LockableBox()

    {

        isLidLocked = false;

    }

    public void LockLid()

    {

        isLidLocked = true;

    }

    public void UnlockLid()

    {

        isLidLocked = false;

    }

    public override void CloseLid()

    {

        if (isLidLocked == false)

            base.CloseLid();

    }

    public override void OpenLid()

    {

        if (isLidLocked == false)

            base.OpenLid();

    }

}

List the values of the data members for each object at the end of the following code:

LockableBox a = new LockableBox();

a.CloseLid();

a.LockLid();

Box b = a;

b.OpenLid();

// Here: what is the internal state of each object?

Answer 1

There is only one object here, with 2 different references.

Status of object:
-------------------
isLidLocked -> True
isLidOpen ->   False

both references a and b are pointing to the above object.