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From: John Harbaugh <john.s.harbaugh2@boeing.com>
Subject: Re: passing pointer of different type to one procedure
Date: 1997/04/17
Message-ID: <33568C14.4337@boeing.com>#1/1
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Newsgroups: comp.lang.ada
Date: 1997-04-17T00:00:00+00:00
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Boaz wrote:
> 
> Hi there,
> 
> I am trying to write a sort procedure for a data base project.  I have 2
> different records.  Instead of having 2 instances for that sort procedure,
> I am thinking to use just one that take a pointer of either one of the
> records type.
> 
> this is my test program but I don't quite sure how to set it up :
> 
> with text_io; use text_io;
> with ada.float_text_io; use ada.float_text_io;
> 
> procedure test is
> 
> type record_pointer is access all record;  <-- error
> 
> type a is record
>         key : float;
>         d : integer;
> end record;
> 
> type b is record
>         key : float;
>         e : float;
> end record;
> 
> rp : record_pointer;
> d1  : aliased a;
> d2      : aliased b;
> 
> procedure sort(p : in record_pointer) is
> begin
>         put(p.key);
> end sort;
> 
> begin
> 
>         d1.key := 1.0;
>         d2.key := 5.0;
>         rp := d1'access;
>         sort(rp);
>         rp := d2'access;
>         sort(rp);
> end test;
Perhaps you could create records as a class hierarchy of tagged types,
then pass a class-wide pointer to your sort routine.

Cheers,

   - John