Thanks Keith. It does help. I have, however figured out another error
with the script in the next lesson.
#!/usr/bin/perl
%words = qw(
fred camel
barney llama
betty alpaca
wilma alpaca
);
print "What is your name? ";
$name = <STDIN>;
chomp ($name);
$original_name = $name; # save for greeting
$name =~ s/W.*//; # get rid of everything after
first word (according to the book)
$name =~ tr/A-Z/a-z/; # lowercase everything
print "The name converted to: $name\n"; # this (according to the book)
should just be the first name.
if ($name eq "randal") { # ok to compare this way now
print "Hello, Randal! How good of you to be here!\n";
} else {
print "Hello, $original_name!\n"; # ordinary greeting
$secretword = $words{$name}; # get the secret word
print "$secretword\n";
if ($secretword eq "") { # oops, not found
$secretword = "groucho"; # sure, why a duck?
}
print "What is the secret word? ";
$guess = <STDIN>;
chomp ($guess);
while ($guess ne $secretword) {
print "Wrong, try again. What is the secret word? ";
$guess = <STDIN>;
chomp ($guess);
}
}
This script expands on the previous script and in fact causes unexpected
results. The book explains that s/W.*// will take the first
non-character (A-z, 0-9, -_) and remove it and everything to the left of
it. To me, that would include spaces, but that is not the behavior I am
getting on my machine. If I enter Fred FLINTstone, the print "The name
converted to: $name\n"; statement, which I added to the script, prints
"fred flintstone", therefore it does not match the array $words.
I am now assuming the space character is allowed as part of the
expression s/W.*//.
Tom Carroll
Dataware Computers
-----Original Message-----
From: Keith Woody [mailto:[EMAIL PROTECTED]]
Sent: Friday, May 10, 2002 1:21 PM
To: Tom Carroll
Cc: [EMAIL PROTECTED]
Subject: Re: [e-smith-devinfo] Perl programmers - help for a lowly
unworthy newbie
Tom,
the -w flag just tells perl to _w_arn you verbally about errors, even if
they aren't fatal.
the error below is referring to the following line of code
...
if ($secretword eq "") { # oops, not found
...
in the case where you type "Fred" or "FRED" or anything that isn't
"fred", $secretword is empty (uninitialized) because %words only has an
entry for "fred". Since $secretword is empty, it sets it to "groucho",
forcing you to use that to exit.
Hope this helps,
-Keith
<keith snip>
"Use of uninitialized value in string eq at ./hello_world_6.pl line 16
<STDIN> line 1."
</keith snip>
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