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From: dankg@volcano.Berkeley.EDU (Dan KoGai)
Newsgroups: comp.lang.c
Subject: Re: Character arrays
Keywords: FORMULA SCANNING
Message-ID: <1990Jul5.091706.10999@agate.berkeley.edu>
Date: 5 Jul 90 09:17:06 GMT
References: <13281@ulysses.att.com>
Sender: usenet@agate.berkeley.edu (USENET Administrator;;;;ZU44)
Reply-To: dankg@volcano.Berkeley.EDU (Dan KoGai)
Organization: ucb
Lines: 25

In article <13281@ulysses.att.com> srn@ulysses.att.com (Shirish R Nadkarni) writes:
>Does anyone have a piece of code that can scan a formula ? I will
>try to explain that a bit:
>
>Suppose I have 4 numbers (these will be stored in variable names, but
>for the time we will assume that they are stored under 1, 2, 3 and 4).
>I need to calculate 
>
>total = 1 * 2 + 3 * 4  OR (1*2) + 3 + 4   OR 1 + (2/3) +4

	Take a look at the source of expr:  expr is a unix utility that
does exactly what you want:  You give formula as an arguments, which
symobols and numbers separated with space.
	I had to do if from scratch in my CS cource.  Maybe it's a good
practice if you do it by yourself.  It was quite benefitial for me.  But
precedence handling was pain in the neck...

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