Pernicious numbers: Difference between revisions
Content added Content deleted
(Added Forth solution) |
m (Forth - simpler primality test) |
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0 |
0 |
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begin |
begin |
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n 0 |
n 0<> |
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while |
while |
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n n 1- and to n |
n n 1- and to n |
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| Line 870: | Line 870: | ||
repeat ; |
repeat ; |
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\ primality test for 0 <= n <= 63 |
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: prime? |
: prime? ( n -- ? ) |
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n 2 < if false exit then |
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1 swap lshift 0x28208a20a08a28ac and 0<> ; |
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n 2 mod 0= if n 2 = exit then |
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n 3 mod 0= if n 3 = exit then |
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5 |
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begin |
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dup dup * n <= |
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while |
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n over mod 0= if drop false exit then |
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2 + |
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n over mod 0= if drop false exit then |
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4 + |
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repeat |
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drop true ; |
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: pernicious? ( n -- ? ) |
: pernicious? ( n -- ? ) |
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