Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!ut-emx!ccwf.cc.utexas.edu
From: mjensen@ccwf.cc.utexas.edu (Marc S. Jensen)
Newsgroups: comp.lang.pascal
Subject: Re: Help Me!!! What's wrong with this simple problem?
Message-ID: <40343@ut-emx.uucp>
Date: 29 Nov 90 05:19:52 GMT
References: <527@shum.UUCP> <19956@oolong.la.locus.com> <28893@shamash.cdc.com>
Sender: news@ut-emx.uucp
Reply-To: mjensen@ccwf.cc.utexas.edu (Marc S. Jensen)
Organization: The University of Texas at Austin
Lines: 36

In article <28893@shamash.cdc.com> mpe@shamash.UUCP (Mike Ebsen) writes:
>What's wrong with this problem in Turbo Pascal 5.0...
>
>      Program test;
>      var
>        i : integer;
>        j : word;
>      begin
>        j:=3;
>        i:=j-10;
>        writeln(j,'     ',i);
>      end.
>
>My compiler tells me that the assignment of -7 into i (an integer) 
>is an error.


The problem is not the -7, but the fact that j is declared as being of
type word. In TP, a word is defined as an unsigned 16-bit data type, 
whereas an integer is a signed 16-bit type. It is therefore possible to
store numbers in a word that cannot possibly fit in an integer. (Numbers
from 32768 through 65535 can be words but not integers.) To safeguard 
against this, the compiler disallows assigning a word value to an integer
variable.
In your example, you could either declare j : integer, or, if you
*need* it to be a word, i : longint or i : word.



-- 

Marc Jensen
mjensen@ccwf.cc.utexas.edu
University of Texas at Austin
-----
"Never attribute to malice that which is adequately explained by stupidity!"