Beefy Boxes and Bandwidth Generously Provided by pair Networks
Welcome to the Monastery
 
PerlMonks  

comment on

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

Perl allows to use arithmetics on string

Here's the code:
#!/usr/local/bin/perl -w use strict; sub step_over_desert # () I won't repeat this mistake anymore!!! { print "Tsock...\n"; } sub cover_the_distance # () I won't repeat this mistake anymore!!! { my ($me, $desert_width, $max_spit_distance, $num_legs, $last_name, + $day_phone, $days_without_water) = @_; my $num_steps=0; while($desert_width) { my $todo = $desert_width * $num_legs; print "$desert_width miles remaining; $todo steps yet to do.\n" +; step_over_desert(); $desert_width--; $num_steps += $num_legs; } print "Steps made: $num_steps\n"; } #cover_the_distance("strong animal", 5, 15, 4, "Mabooka", "(123)-456-7 +890", -1); cover_the_distance("strong animal", "five thousand miles", 15, 4, "Mab +ooka", "(123)-456-7890", -1); 1;

Don't try it at home

Well, I recommend at the very least to redirect the output to a file:-).

Why people do this?

Again, the main reason: because it allows you. One may expect either a compile-time error or a run-time exception. But Perl allows you to shoot your own foot.
Actually, this is an obfuscated (starting to love the word) code from a real-life app. The real application would send a query over the wire to the server,
get a responce line --
-- that should look smth. like this:
200 OK 578
-- meaning " there're 578 lines yet to read from the socket,
parse this line and create a loop:
while($numlines) { get_next_one(...); $numlines--; ... }
Well guess what? Once in 10000 times the server would get tired and send a garbled status line -- smth. like:
200 OK whatever,man
and
(while "whatever,man"--) {....}
will start the almost infinite loop. (Try the code above).

Solution

Be aware.
use int($n).
Ask your new hires during the inteview: "What is the result of the following operation:
"Larry"--;
-?.

In reply to Re^2: Example 2: incrementing "something" by Mabooka-Mabooka
in thread Common Beginner Mistakes by chromatic

Title:
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?
Username:
Password:

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

How do I use this? | Other CB clients
Other Users?
Others taking refuge in the Monastery: (4)
As of 2021-09-20 22:54 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found

    Notices?