Re: cs 3304

Stephen Edwards (edwards@CS.VT.EDU)
Wed, 10 Oct 2001 08:50:11 -0400

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Message-ID:  <3BC44403.B1A947AC@cs.vt.edu>
Date:         Wed, 10 Oct 2001 08:50:11 -0400
From: Stephen Edwards <edwards@CS.VT.EDU>
Subject:      Re: cs 3304

adrian porter asked two excellent questions:
>
> What do we do about idiv and irem by 0?
>
> '(iconst -13 iconst 0 idiv)
> '(iconst -13 iconst 0 irem)

Good question--I have slightly modified the program description on the
web site to add a separate error message for this kind of error.

> Also, what are we supposed to do about the remainder of negative operations?
>
> '(iconst -13 iconst 4 irem ireturn)

Use the Scheme numeric function "remainder" to compute the result of an
irem command. For the above example, (remainder -13 4) returns -1.

                                -- Steve

--
Stephen Edwards            604 McBryde Hall          Dept. of Computer Science
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