Ethiopian multiplication: Difference between revisions
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(→{{header|Perl 6}}: modernize) |
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=={{header|Perl 6}}== |
=={{header|Perl 6}}== |
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{{works with|Rakudo Star|2010-08}} |
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<lang perl6>sub halve (Int $n is rw) { $n div= 2 } |
<lang perl6>sub halve (Int $n is rw) { $n div= 2 } |
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sub double (Int $n is rw) { $n *= 2 } |
sub double (Int $n is rw) { $n *= 2 } |
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sub even (Int $n --> Bool) { $n %% 2 } |
sub even (Int $n --> Bool) { $n %% 2 } |
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sub |
sub ethiopic-mult (Int $a is copy, Int $b is copy --> Int) { |
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my Int $r = 0; |
my Int $r = 0; |
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while $a { |
while $a { |
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} |
} |
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return $r; |
return $r; |
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} |
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}</lang> |
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say ethiopic-mult(17,34);</lang> |
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{{out}} |
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<pre>578</pre> |
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More succinctly using implicit typing, primed lambdas, and an infinite loop: |
More succinctly using implicit typing, primed lambdas, and an infinite loop: |
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<lang perl6>sub |
<lang perl6>sub ethiopic-mult { |
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my &halve = * div= 2; |
my &halve = * div= 2; |
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my &double = * *= 2; |
my &double = * *= 2; |
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double $b; |
double $b; |
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} |
} |
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} |
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}</lang> |
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say ethiopic-mult(17,34);</lang> |
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More succinctly still, using a pure functional approach (reductions, mappings, lazy infinite sequences): |
More succinctly still, using a pure functional approach (reductions, mappings, lazy infinite sequences): |
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<lang perl6>sub halve { $^n div 2 } |
<lang perl6>sub halve { $^n div 2 } |
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sub even { $^n %% 2 } |
sub even { $^n %% 2 } |
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sub |
sub ethiopic-mult ($a, $b) { |
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[+] |
[+] ($b, &double ... *) |
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Z* |
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map { $^column_2 if !even $^column_1 }, |
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($a, &halve ... 0).map: { not even $^n } |
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} |
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}</lang> |
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say ethiopic-mult(17,34);</lang> |
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(same output) |
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=={{header|PHP}}== |
=={{header|PHP}}== |
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