Path: utzoo!utgpu!news-server.csri.toronto.edu!qucdn!spraggej
Organization: Queen's University at Kingston
Date: Wednesday, 28 Nov 1990 09:27:37 EST
From: John G. Spragge <SPRAGGEJ@QUCDN.QueensU.CA>
Message-ID: <90332.092737SPRAGGEJ@QUCDN.QueensU.CA>
Newsgroups: comp.lang.pascal
Subject: Re: Help Me!!! What's wrong with this simple problem?
References: <527@shum.UUCP> <19956@oolong.la.locus.com> <28893@shamash.cdc.com>

In article <28893@shamash.cdc.com>, mpe@shamash.cdc.com (Mike Ebsen) says:
>
>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 expression j-10 is evaluated as a word expression. The result
of subtracting 10 from 3 in a word will not be -7, since the
word is unsigned: it is 65536-7, or 65529. Since integers only
range from -32768 to 32767, the compiler detects an error.