Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!gatech!udel!udccvax1!udccpyr1!mikej
From: mikej@pyr1.acs.udel.EDU (Michael Jacobs)
Newsgroups: comp.lang.pascal
Subject: Re: function returning a record?
Keywords: goofy types, functions
Message-ID: <2994@udccvax1.acs.udel.EDU>
Date: 3 Mar 89 20:39:00 GMT
References: <2012@pur-phy> <790@rpi.edu> <2016@pur-phy>
Sender: usenet@vax1.acs.udel.EDU
Reply-To: mikej@pyr1.acs.udel.EDU (Michael Jacobs)
Organization: University of Delaware
Lines: 55

>>FUNCTION Complex_Add(z1,z2 : complex) : comples;
>
>Though I understand what you are getting at, a posting just previous
>to yours points out that the function may not be anything other than
>simple types and pointers.  So what that means is that your solution

Then declare

Type
  Complex_Number =
    Record
    X, Y : Real
    End;
  Complex = ^Complex_Number;

Procedure Complex_Allocate ( Var C : Complex );

Begin
New ( C )
End;

Function Complex_Add ( A, B : Complex ) : Complex;

----

Everytime you want to use a complex number, you'd have to create a
record and pointer for it (using Complex_Allocate ( perhaps even
use a FreeList algorithm for it ) ) and in Complex_Add, two already
existing pointers at sent in (or some VERY serious barfing will take
place) and a new third on is returned.

Another procedure and two more functions will be needed:

Procedure Load_Complex ( x,y : real; var C : Complex );
Function Real_Part ( C : Complex ) : Real;
Function Imaginary_Part ( C : Complex ) : Real;

OR!

using your original implementation of the type

Procedure Complex_Add ( A, B : Complex; Var C : Complex );

add 'em up and stick 'em in C.  That should work.

The first thing I talked about with the pointers and billions of functions
and procedures is a lot more formal and will probably get more better
grades in CIS theory/programming classes, more the second was is alot
easier.



Mike J, The Grey Sysop...   |  Ancient Spirits of Evil, transform this
Temporal Hitchhiker         |  decayed form into Mumm-ra, the Ever Living!
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