Mersenne primes: Difference between revisions
→{{header|AppleScript}}: Added more efficient version. Corrected the original's <syntaxhighlight…> tags.
(→{{header|Ruby}}: Add Ruby) |
(→{{header|AppleScript}}: Added more efficient version. Corrected the original's <syntaxhighlight…> tags.) |
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=={{header|AppleScript}}==
<syntaxhighlight lang="
on isPrime(integ)
set isComposite to ""
Line 138:
end repeat
</syntaxhighlight>
----
Or more efficiently:
<syntaxhighlight lang="applescript">on isPrime(n)
if (n < 4) then return (n > 1)
if ((n mod 2 is 0) or (n mod 3 is 0)) then return false
set {i, max} to {5, (n ^ 0.5) div 1}
repeat until (i > max)
if ((n mod i is 0) or (n mod (i + 2) is 0)) then return false
set i to i + 6
end repeat
return true
end isPrime
on join(lst, delim)
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to delim
set txt to lst as text
set AppleScript's text item delimiters to astid
return txt
end join
on mersennePrimes()
set output to {"Mersenne primes within AppleScript's number precision:"}
-- Special-case 2 ^ 2 - 1.
set end of output to "2 ^ 2 - 1 = 3"
set p to 1 -- Otherwise test odd-numbered powers of 2.
try -- Survive the "numeric operation too large" error when it occurs.
repeat
set p to p + 2
if ((isPrime(p)) and (isPrime(2 ^ p - 1))) then ¬
set end of output to "2 ^ " & p & " - 1 = " & (2 ^ p div 1 - 1)
end repeat
end try
return join(output, linefeed)
end mersennePrimes
mersennePrimes()</syntaxhighlight>
{{output}}
<syntaxhighlight lang="applescript">"Mersenne primes within AppleScript's number precision:
2 ^ 2 - 1 = 3
2 ^ 3 - 1 = 7
2 ^ 5 - 1 = 31
2 ^ 7 - 1 = 127
2 ^ 13 - 1 = 8191
2 ^ 17 - 1 = 131071
2 ^ 19 - 1 = 524287
2 ^ 31 - 1 = 2.147483647E+9"</syntaxhighlight>
=={{header|Arturo}}==
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