From:	Leon Heller <leon AT lfheller DOT demon DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Random interger numbers
Date:	Tue, 24 Mar 1998 08:49:10 +0000
Organization:	at home
Distribution:	world
Message-ID:	<cU1PCDAGO3F1Ew3D@lfheller.demon.co.uk>
References:	<01bd56dd$5d636c80$0f02000a AT frank DOT mtsu DOT edu DOT frank DOT mtsu DOT edu>
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To:	djgpp AT delorie DOT com
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In article <01bd56dd$5d636c80$0f02000a AT frank DOT mtsu DOT edu DOT frank DOT mtsu DOT edu>,
Nathan Cournia <nac2b AT frank DOT mtsu DOT edu> writes
>       How do I produce a random interger number between 0 and n.  Right now 
>I'm
>using the following code:
>
>       return (((int)((double)rand()/(double)RAND_MAX))*n);
>
>       Unfortunately this equation always produces the result of 0.  What I 
>need
>is a function that will act as a (n) sided dice.  Thanks for the help.
>
>       Nathan
>
>

Off-topic for this newsgroup, but anyway...

        1 + (int) ((float) n * rand()/(RAND_MAX + 1.0))

generates pseudo-random numbers between 1 and n.

Don't be tempted to use the simpler

        1 + (rand() % n)

as it uses the lower-order bits, and might not be very random. If you
used random() rather than rand(), the latter *might* be OK.

The above is based on the Numerical Recipes in C book.

Leon
-- 
Leon Heller: leon AT lfheller DOT demon DOT co DOT uk http://www.lfheller.demon.co.uk
Amateur Radio Callsign G1HSM    Tel: +44 (0) 118 947 1424
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