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From: Slomcenski.WBST@Xerox.COM
Newsgroups: comp.lang.pascal
Subject: Re: TURBO Pascal READ
Message-ID: <7085@brl-adm.ARPA>
Date: Fri, 24-Apr-87 09:02:59 EST
Article-I.D.: brl-adm.7085
Posted: Fri Apr 24 09:02:59 1987
Date-Received: Sat, 25-Apr-87 11:59:34 EST
Sender: news@brl-adm.ARPA
Lines: 41

>
>readln(r,a,b);
>writeln(r:8:3,a,b);
>
>

>The input line contains a real number and two characters:
>12.34 ET
>The output is:
>  12.340 E
>
>an input of:
>12.34ET
>brings up an I/O error 10.

The catch is that the format of a real may (or may not) contain the
scientific notation 'E+xx' or 'E-xx' following the digits. In the first
case, readln
interprets '12.34' as the real (the number terminates when TURBO finds
any
char that is not part of the real format, in this case ' '). In the
second
case, readln sees the scientific notation '12.34E' and expects the next
char to
be a '+', '-', or the digits indicating an exponent. When it encounters
the
'T' -- it generates the I/O error 10.

>So I think there must be always a blank after a read of a number.
>

Input of a number DOES NOT have to be followed by a ' '!! In fact, in
the
first case, the blank is interpreted as the value for the char variable
a.
The second case would have worked fine except that the char after the
digits happened to be 'E' which is STILL part of a real number
representation.

  ~Bob