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Re: performance of perl vs java

by Lotus1 (Priest)
on Oct 27, 2011 at 17:26 UTC ( #934191=note: print w/replies, xml ) Need Help??

in reply to performance of perl vs java

I noticed that the comparison is not the same between the two versions.

  • Java version:   if ($composite == 1)
  • Perl version:   if (! $composite)
  • The Perl version is finding primes where the Java version is just printing the first 100 numbers that come along. That is why it was so fast.

    #!/usr/bin/perl use warnings; use strict; my $maxprimes=100; my $value=1; my $count=0; my $start=time(); print "Printing the first $maxprimes numbers that are prime... \n"; while ($count < $maxprimes) { $value++; my $composite=0;#false OUTER: for (my $i=2; $i < $value; $i++) { INNER: for (my $j=$i; $j<$value; $j++) { if (($j*$i) == $value) { $composite=1;#true last OUTER; } } } # if (! $composite) #this works if ($composite == 1) #from the java section, doesn't work { $count++; print "$value is prime\n"; } } my $time = (time() - $start); print "Took $time seconds.";

    Update: It looks like it prints the non-prime numbers.

    Printing the first 100 numbers that are prime... 4 is prime 6 is prime 8 is prime 9 is prime 10 is prime 12 is prime 14 is prime 15 is prime . . . 128 is prime 129 is prime 130 is prime 132 is prime 133 is prime Took 0 seconds.

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