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Re: Re: Re: bugs...

by tachyon (Chancellor)
on Mar 15, 2002 at 13:00 UTC ( #151970=note: print w/replies, xml ) Need Help??

in reply to Re: Re: bugs...
in thread subroutine not returning expected value

$#retval gives the index of the last element in the array. If an array is empty this will be -1. If it is zero then the array contains one element. Here is a demo:

my @retval; print "the last index of \@retval is $#retval\n"; print "the number of *elements* in \@retval is ", scalar @retval, "\n" +; push @retval, 'one value'; print "the last index of \@retval is $#retval\n"; print "the number of *elements* in \@retval is ", scalar @retval, "\n" +; push @retval, 'another value'; print "the last index of \@retval is $#retval\n"; print "the number of *elements* in \@retval is ", scalar @retval, "\n" +;

I fully understand the shorthand BTW ;-) The longhand is for your debugging benefit as your code craps out after this as you demonstrate! Also as noted you do not show the method where the error actually occurs. While using OO perl is a great idea your data structures are poor and do not take full advantage of the usual anonymous hash structure. Here is a very brief demo of how I might approach the problem:

package Item; use Data::Dumper; my @items; # initialise an array of item objects from our data while (<DATA>) { chomp; next unless $_; my $item = new Item; my ($id, $quant ) = split ','; $item->id($id); $item->quant($quant); push @items, $item; } print Dumper \@items; # now sell one of each item for my $item (@items) { $item->quant(-1); } print Dumper \@items; # now print out the id and quantities print "\n\nid quant\n"; for my $item (@items) { print $item->id, "\t", $item->quant, "\n"; } ############################## sub new { my $self = shift; return bless {}, $self; } # get or set id sub id { my ($self, $cid) = @_; $self->{'id'} = $cid if defined $cid; return $self->{'id'}; } # get or set numbers in stock sub quant { my ($self, $change) = @_; $self->{'quant'} += $change if defined $change; return $self->{'quant'} } __DATA__ item 1,10 item 2,20 item 3,30




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