• Dune <not.yet yahoo.com> Nov 28 2006
• Stewart Gordon <smjg_1998 yahoo.com> Nov 28 2006
• Dune <not.yet yahoo.com> Nov 28 2006
• David L. Davis <SpottedTiger yahoo.com> Nov 28 2006

Dune <not.yet yahoo.com> writes:

Hi,
trying to get D into my brain but somehow I'm not in sync yet...

This works (from the docs):

struct Foo {
  public:
  int data() { return m_data; }                  // read property
  int data(int value) { return m_data = value; } // write property

  private:
  int m_data;
}

void main() {
  Foo f;
  f.data = 3; // same as f.data(3);
  printf ("%d", f.data + 3); // same as return f.data() + 3;
}

This doesn't:

class Foo {
  public:
  int data() { return m_data; }                  // read property
  int data(int value) { return m_data = value; } // write property

  private:
  int m_data;
}

void main() {
  Foo f;
  f.data = 3; // same as f.data(3);
  printf ("%d", f.data + 3); // same as return f.data() + 3;
}

Thanks for any help

Dune

BTW: Maybe I will bother you guys/gals even more... depending on my grasping
skills ;)

Stewart Gordon <smjg_1998 yahoo.com> writes:

Dune wrote:
<snip>
 This doesn't:
 
 class Foo {
   public:
   int data() { return m_data; }                  // read property
   int data(int value) { return m_data = value; } // write property
 
   private:
   int m_data;
 }
 
 void main() {
   Foo f;
   f.data = 3; // same as f.data(3);



Welcome to D.

Classes in D have reference semantics.  That is, by declaring a Foo, you 
are declaring not an object, but a reference to one.  Initially, any 
reference is null, i.e. it doesn't refer to anything.  Before you can do 
anything with it, you must make it refer to an object.

     f = new Foo;

This creates a new object of type Foo, and makes f refer to it.  Once 
that's done, then you can do stuff with it.

Stewart.

-- 
-----BEGIN GEEK CODE BLOCK-----
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My e-mail is valid but not my primary mailbox.  Please keep replies on 
the 'group where everyone may benefit.

Dune <not.yet yahoo.com> writes:

Duh!

While reading your post it was obvious that I forgot the essential stuff.
Thanks.

Dune

David L. Davis <SpottedTiger yahoo.com> writes:

Hi Dune,


    You needed the following line change "Foo f = new Foo;" since
a class is an object, you needed to create it first before you
using it.

class Foo {
  public:
  int data() { return m_data; }                  // read property
  int data(int value) { return m_data = value; } // write property

  private:
  int m_data;
}

void main() {
  Foo f = new Foo;
  f.data = 3; // same as f.data(3);
  printf ("%d", f.data + 3); // same as return f.data() + 3;
}

David L