Where is Special Characters Reference

[flywire]

Where is the reference for special characters such as hex and pointer etc?

[marcov]

In the reference manual?  & is octal, % is binary and $ is hex.    # is character (and can be combined with the others, so #$15 is the character with hexcode 15)

[flywire]

Yes, this is what I was looking for.

1.1 Symbols

• The following characters have a special meaning:
  ... ^ @ ... $ # & %
1.6 Numbers

• $ Hex, & Octal, % Binary
1.8 Character strings

• # Char

Now, what about the ^ @ characters which first appear in 3.2 Character types?
^ is pointer and @ is an address but it doesn't mean much to me.


Thanks

[Bart]

Code: [Select]

type
  TFoo = record X: Integer; end;
  PFoo = ^TFoo; //PFoo is a pointer to a TFoo structure
var
  Foo: TFoo;
  P: PFoo;
begin
  Foo.X := 1;
  P := @Foo; //P now points to Foo
  writeln(Foo.X); //shows 1
  writeln(P^.X); //shows 1, the ^ after is called dereferencing
  Foo.X := 2;
  P^.X := 3;
  writeln(Foo.X); //shows 3, since P^.X is the same as Foo.X
end.

Bart

[flywire]

A reference in the wiki under tutorials has a good page on pointers:  http://www.delphibasics.co.uk/Article.asp?Name=Pointers

Two snippets:

• myCharPtr := Addr(myString);
  Neil explains that 'the @ character can equally be used instead of the Addr function'. This does it for me - it's just a function.
• ShowMessage(myCharPtr^)
  "...we use the ^ character at the end of the pointer name to refer to what the pointer points to." So read it as 'points to' like := is read becomes.

[flywire]

A good article on pointers by Rudy Velthuis: http://rvelthuis.de/articles/articles-pointers.html

[marcov]

Note that (OBJ)FPC modes also require @ to assign/pass procedure variables. This was done to disambiguate some special case.