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40 lines
686 B
Plaintext
40 lines
686 B
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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none
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LIBRARY
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FULL zpprime(ZVALUE z)
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SEE ALSO
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nextprime
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