Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

When continued_fraction($x,$y,$z) is called, the parameters $x, $y, $z are assigned to the list @_ which is visible locally inside the sub and can be addressed in the usual way like $_[0], $_[1]...
Here, @_[0,1] is an array-slice equivalent to the list ($_[0], $_[1]).

BTW: Accessing @_ is "call-by-reference" style. Assigning to i.e $_[0] inside the sub would change callers $x in the example above. Usually, you would create a local copy, i.e. my (@args) = @_;. Accessing @_ might be used here for speed-optimisation or because of bad style?

Perl historically had no strict function/sub signatures, so you can pass any number of arguments without Perl complaining - that feature was added recently (Perl 5.20, experimental).

$n = $_[2] // 100; is the same as $n = defined($_[2]) ? $_[2] : 100;
So, if the third - obviously optional parameter is given, it is used. If not, the default value 100 is assigned to $n.

In reply to Re: Rosetta Code Error or $n // 100 by Perlbotics
in thread Rosetta Code Error or $n // 100 by pgmer6809

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?

What's my password?
Create A New User
Domain Nodelet?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others romping around the Monastery: (4)
As of 2022-08-15 01:07 GMT
Find Nodes?
    Voting Booth?

    No recent polls found