in reply to finding highest number

It's because you're only comparing the current and next numbers in the array. The way I would do it, is keep track of the highest number in another variable. The variable is initialized to the first number in the array. 
use strict;

my @array = (1, 5, 4, 10, 20, 2, 1, 3, 7);
my $highest = $array[0];

foreach (@array) {
    $highest = $_ if $_ > $highest;
}

print $highest;

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Which gives me 20. I'm sure there are prettier ways, but this seems to work.

Update: and of course, the perlish way would be to use sort. duh. ++newrisedesigns. I need a coffee.

--
"I don't intend for this to take on a political tone. I'm just here for the drugs." --Nancy Reagan

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Re^2: finding highest number
by diotalevi (Canon) on Dec 05, 2002 at 13:18 UTC

    No... that would be known as the slow way. This is an operation which should only have to traverse the array *once* where sort() has higher overhead (perhaps gjb has it right as O(n*log(n)) versus O(n)).

    The better answer is to use something akin to what you posted. I'd want to check for undefined values as well. For an answer I just copied right from a toy mapping app I just coded up last night.

    sub max { my $m;
          for (@_) {
            next unless defined;
            $m = $_, next unless defined $m;
            $m = $_, next if $m < $_;
          }
          $m }

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    __SIG__
use B;
printf "You are here %08x\n", unpack "L!", unpack "P4", pack
  "L!", B::svref_2object(sub{})->OUTSIDE;

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Re: Re: finding highest number
by Anonymous Monk on Dec 05, 2002 at 13:09 UTC
    thanks LTjake this is cool, but how could you adapt it to calculate second and third highest numbers also??
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          how could you adapt it to calculate second and third highest numbers?

      something like:
      use strict;

my @array = (1, 5, 4, 10, 20, 2, 1, 3, 7);
my @hi = (0) x 3;                # '0' assumes positive #'s

foreach (@array) {
   $_ <= $hi[0] and next;
   @hi = (sort $a<=>$b, @hi, $_)[-3..-1];
}

print "@hi";

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      (untested)   (and, as said, of course the sort method would be better, at least for small arrays, and would be even more better for finding the top three values:  (sort ..., @array)[-3..-1] )

        p
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