Re: Overriding abstract class fields

[Basile B. via Digitalmars-d-learn]

On Thursday, 1 September 2016 at 11:09:18 UTC, slaid wrote:
I have a snippet:
How do I override this height field?

Thanks

The field height is not overridden. In C you have two "height". 
Since your array is of type A[], map takes A.height.

abstract class A
{
    int height = 0;
}

class B : A {}

class C : A
{
    int height = 1;
}

void main()
{
    writeln((new C).height); // prints 0, the height of C
    writeln((cast(A)(new C).height); // prints 1, the height of A
}

Only methods are virtual. To solve the problem you can create a 
virtual getter:

°°°°°°°°°°°°°°°°°°°°°°
abstract class A
{
    int height();
}

class B : A
{
    override int height(){return 0;}
}

class C : A
{
    override int height(){return 1;}
}
°°°°°°°°°°°°°°°°°°°°°°

But since height is only a field you can just use the same 
variable and set the value in the constructor (for example)

°°°°°°°°°°°°°°°°°°°°°°
abstract class A
{
    int height;
}

class B : A
{
    this(){height = 0;}
}

class C : A
{
    this(){height = 1;}
}
°°°°°°°°°°°°°°°°°°°°°°