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From: userW6BP@um.cc.umich.edu
Newsgroups: comp.lang.pascal
Subject: Re: What's wrong with this:
Message-ID: <W6BP672125885@um.cc.umich.edu>
Date: 20 Apr 91 05:38:05 GMT
References: <1991Apr20.011454.25016@javelin.sim.es.com>
Sender: usenet@terminator.cc.umich.edu (usenet news)
Organization: University Of Michigan, Ann Arbor
Lines: 32

In article <1991Apr20.011454.25016@javelin.sim.es.com>, 
tpehrson@javelin.sim.es.com writes:
>why doesn't this work:
>
>function upper(I:string):string;
> var z:integer; 
> begin
>  for z:=1 to length(I) do
>  if (ord(I[z])>96) and (ord(I[z])<123) then I[z]:=upcase(I[z]);
> end;
>
>i have a feeling i'm overlooking the obvious ...
 
Yes, you are. 
 
You need to set the function to the value of the altered string:
 
FUNCTION upper(I:string):string;
 
VAR
  z : INTEGER;
 
BEGIN 
  FOR z := 1 TO LENGTH(I) DO
      IF (ORD(I[z]) > 96) AND (ORD[I[z]) < 123)
         THEN I[z] := UPCASE(I[z]);
 
  upper := I;     (* This is what you were missing *)
END;
 
 
--Allan