Hello Parmenides,

Since this is a learning exercise, here are a couple of points to add to the excellent advice given by CountZero above:

• Prefer the use warnings; pragma to the -w command line flag. The latter applies globally, so it may give warnings for modules you use in your code but over which you have no control. The former is lexically scoped, and can be turned on and off as needed. See warnings.


• Despite the superficial similarities, Perl is not C, so you don’t need to declare your variables at the start of a block. It is better practice to declare lexical variables at the point of first use. For example:

  chomp(my $infile = <STDIN>);
  [download]

By the way, CountZero’s advice about double-quoting variables is explained in What's wrong with always quoting "$vars"?.

(Also, please have a look at How do I compose an effective node title?.)

HTH,

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.