NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/comp/lang/pascal/7869

Internet Message Format | 1993-01-05 | 1.6 KB

Path: sparky!uunet!math.fu-berlin.de!mailgzrz.TU-Berlin.DE!mailgzrz.TU-Berlin.DE!news
From: [e-mail] (Carsten Schultz)
Newsgroups: comp.lang.pascal
Subject: Re: Passing functions as params in Turbo Pascal
Date: 5 Jan 1993 16:51:35 GMT
Organization: ZRZ/TU-Berlin
Lines: 35
Distribution: world
Message-ID: <[e-mail]>
References: <[e-mail]>
Reply-To: [e-mail] (Carsten Schultz)
NNTP-Posting-Host: pizza.fb10.tu-berlin.de

In article <[e-mail]> <[e-mail]> writes:
> While ISO Standard Pascal (as defined by Jensen and Wirth) allows
> passing functions as parameters to other functions or procedures,
> Turbo Pascal 6.0 that I use at school, declares an error that an
> identifier is expected, which means that I cannot pass functions
> as parameters in the standard way.  For all you TP experts on the
> net, is there a workaround? e.g. something like defining pointers
> to functions as one might do in C?  Thanks in advance for any help
> in this matter. I desperately need this feature, so that I don't
> have to write a separate integration procedure for every function
> I want to integrate.
>

Hi,

I just give an example, please refer to the manual for details.

function Ident(x: real): real; far;
begin
  Ident:=x;
end;

type realFunc= Function(x: real): real;

function Integrate(f: realFunc; a, b: real): real;
begin
  Integrate:=(b-a)*(f(a)+f(b))/2;
end;



I did not test this.
The above functions are useful for demonstration purposes only.

Carsten