How to use Unit files in Delphi

Question

I'm just trying to get the hang of separate units to make my code more encapsulated. I'm trying to get the public/private declarations of my methods sorted out, so I can call them from other units that use testunit. In this example I want to make hellofromotherunit public, but stickletters private.

unit testunit;    

interface

uses
  Windows, Messages, Dialogs;    

implementation

function stickletters(a,b:string):string;
begin
  result:=a+b;
end;

procedure hellofromotherunit();
begin
 showmessage(stickletters('h','i'));
end;

end.

I could not seem to copy the private/public structure from other units as in:

Type
private
function stickletters(a,b:inter):integer;
public
procedure hellofromotherunit();
end

Answer 1

The Unit structure looks a bit like the public/private sections from objects, you could say it is their forerunner. But the syntax is different.

You only have to declare the method header in the interface section, as in:

interface
  procedure hellofromotherunit();

implementation
  procedure hellofromotherunit(); begin .. end;

Only one of each section allowed.