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From: leonard@bucket.UUCP (Leonard Erickson)
Newsgroups: comp.lang.pascal
Subject: Re: Funny evaluation of functions
Keywords: functions, precedence
Message-ID: <1643@bucket.UUCP>
Date: 24 Aug 89 22:41:41 GMT
References: <614@lehi3b15.csee.Lehigh.EDU>
Organization: Rick's Home-Grown UNIX; Portland, OR.
Lines: 35

edkay@lehi3b15.csee.Lehigh.EDU (Ed Kay) writes:

<   The following code produces 25 as output in Turbo Pascal 4.0.  Can
<anyone explain what is going on?
< 
<  var y:integer;

<  Function one(var x:integer):integer;
<  begin
<   x:=x+1;
<   one:=x;
<  end;
< begin
<  y:=4;
<  writeln(output,y*one(y));
< end.

by using "Var x:integer" instead of "x:integer" in the function header
you've told the computer to use the passed variable rather than a copy
of it. So when the function is executed it uses "y" everyplace that
it says "x". 

if you take out the "var" in the header, the program will output 20.
if you change the body from:
	x:=x+1;
	one:=x;
to:
	one:=x+1;
you'll get the same effect.

-- 
Leonard Erickson		...!tektronix!reed!percival!bucket!leonard
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