Re: "Common" variables?

2 Jan 2003

      Hi!

On Thu, Jan 02, 2003 at 09:55:05AM +0100, Silvio a Beccara wrote:
...
I want the units to share the same, initialised variables.
Just use a unit, where all common variables are defined.

Example:

{ B1: Unit, where rho is defined }
unit B1;

interface

var
  Rho: Real;

implementation

to begin do
  begin
    Rho := 0.01
  end;

end.

{ B2: Unit uses Rho }
unit b2;

interface

procedure UseRho;

implementation

uses b1;

procedure UseRho;
begin
  WriteLn ('Rho is in B2: ', Rho : 0 : 3)
end;

end.

{ "Main"-Program Foo }
program Foo;

uses
  b1, b2;

begin
  WriteLn (Rho : 0 : 3);
  UseRho
end.

Please note, that global variables are a place of hard to find bugs
(e.g. local variables might shadow global variables).

It is better to use routines having parameters:

function Calculate (MyRho: Real): Real;
begin
  { do some calculations }
  { ... }
  WriteLn ('MyRho is: ', MyRho : 0 : 3);
  Calculate := { ... } Sin (MyRho)
end;

Eike

Re: "Common" variables?

Eike Lange