Order two numerical lists: Difference between revisions

=={{header|Perl}}==

<lang Perl>#!/usr/bin/perl -w

use strict ;

sub orderlists {

my $firstlist = shift ;

my $secondlist = shift ;

my $first = shift @{$firstlist } if @{$firstlist} ;

my $second ;

#keep stripping elements from the first list as long as there are any

#or until the second list is used up!

while ( @{$firstlist} ) {

if ( @{$secondlist} ) { #second list is not used up yet!

$second = shift @{$secondlist} ;

if ( $first < $second ) {

return 1 ;

}

if ( $first > $second ) {

return 0 ;

}

}

else { #second list used up, defined to return false

return 0 ;

}

$first = shift @{$firstlist} ;

}

return 0 ; #in all remaining cases return false

}

my @firstnumbers = ( 43 , 33 , 2 ) ;

my @secondnumbers = ( 45 ) ;

if ( orderlists( \@firstnumbers , \@secondnumbers ) ) {

print "The first list comes before the second list!\n" ;

}

else {

print "The first list does not come before the second list!\n" ;

}

</lang>