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66 lines
1.8 KiB
Plaintext
66 lines
1.8 KiB
Plaintext
NAME
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prevprime - nearest prime less than specified number
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SYNOPSIS
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prevprime(n [,err])
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TYPES
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n real
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err integer
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return positive integer or err
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DESCRIPTION
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If n is an integer and 2 < n < 2^32, prevprime(n) returns the
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nearest prime less than n.
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If n <= 2 or >= 2^32 or n is fractional, prevprime(n, err)
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returns the value of err.
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Other cases cause a runtime error.
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EXAMPLE
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> print prevprime(10), prevprime(100), prevprime(1e6)
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7 97 999983
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> print prevprime(2,-99), prevprime(2^32,-99)
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-99 -99
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> print prevprime(2)
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pprime arg 1 is <= 2
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LIMITS
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2 < n < 2^32
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LINK LIBRARY
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FULL zpprime(ZVALUE z)
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SEE ALSO
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nextprime
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## Copyright (C) 1999 Landon Curt Noll
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##
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## Calc is open software; you can redistribute it and/or modify it under
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## the terms of the version 2.1 of the GNU Lesser General Public License
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## as published by the Free Software Foundation.
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##
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## Calc is distributed in the hope that it will be useful, but WITHOUT
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## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
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## Public License for more details.
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##
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## A copy of version 2.1 of the GNU Lesser General Public License is
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## distributed with calc under the filename COPYING-LGPL. You should have
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## received a copy with calc; if not, write to Free Software Foundation, Inc.
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## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
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##
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## @(#) $Revision: 29.1 $
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## @(#) $Id: prevprime,v 29.1 1999/12/14 09:16:03 chongo Exp $
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## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/prevprime,v $
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##
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## Under source code control: 1995/12/18 12:34:58
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## File existed as early as: 1995
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##
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## chongo <was here> /\oo/\ http://reality.sgi.com/chongo/
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## Share and enjoy! :-) http://reality.sgi.com/chongo/tech/comp/calc/
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