Question

I can’t wrap my head around why m() in class a can access x and y through the b class and b class object if x and y are private. I know that when b inherits from a, b receives private members from a even though they can’t be used by b. But what is strange to me is that b members can’t use x and y, and classes other than a can’t get at the variables through b class and b class object, yet m() can access x and y through the b class and b class object.

Can someone explain this to me using a general rule that I missed or maybe an explanation about how the compiler does this ‘giving’ of base members to derived classes?

class a
{
    private int x;
    private static int y;

    static void m()
    {
        b bobj = new b();
        int mm = bobj.x;
        int rr = b.y;


    }

    void n()
    {
        b bobj = new b();
        int mm = bobj.x;
        int rr = b.y;
    }
}

class b : a
{
    private int u;
    private static int v;

    static void o()
    {

    }

    void p()
    {

    }
}

Answer 1

I can’t wrap my head around why m() in class a can access x and y through the b class and b class object if x and y are private

Code within a class declaration can access any private members declared by that class – it’s as simple as that. So code within a can’t access private variables declared in b, but it can access private variables declared in a via an instance of a which also happens to be an instance of b.

Note that this line:

int rr = b.y;

is effectively converted to

int rr = a.y;

y is only declared by a – if it were really declared by b, it wouldn’t be accessible.

See section 3.5 of the C# 4 language specification for more details.