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Re: Losing or overwritting values

by RhetTbull (Curate)
on Jan 05, 2003 at 01:22 UTC ( #224349=note: print w/ replies, xml ) Need Help??


in reply to Losing or overwritting values

Here's the problem (or one of them):

while (<USEDPW>) { my $pw = @chars[map{rand @chars} (1..17)]; } unless ($_ ne my $usedpw) { print "Your unique ID is: $pw\n"; } my $pw; open(USEDPW, "> $usedpw") or die "crap on me for writing $!"; flock USEDPW, 2; print USEDPW "$pw\n";
You have 2 separate variables named $pw. You used my which is a Good Thing but forgot that my lexically scopes your variables. That means that the my $pw inside the while(<USEDPW>) loop is a completely different variable than the one declared outside the loop. pfaut fixed it in his post but didn't tell you why he did it. You need to declare the $pw variable outside the loop so it stays in scope. For example:
#notice we declare it OUTSIDE the loop my $pw; while (<USEDPW>) { $pw = @chars[map{rand @chars} (1..17)]; } unless ($_ ne my $usedpw) { print "Your unique ID is: $pw\n"; } open(USEDPW, "> $usedpw") or die "crap on me for writing $!"; flock USEDPW, 2; print USEDPW "$pw\n";
You should have gotten a "Use of uninitialized value in print" warning when you ran your code.


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