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POPerl illegal division by zero
 

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    <p>I am trying to run this Perl program.</p> <pre><code>#!/usr/bin/perl # --------------- exchange.pl ----------------- &amp;read_exchange_rate; # read exchange rate into memory # now let's cycle, asking the user for input... print "Please enter the amount, appending the first letter of the name of\n"; print "the currency that you're using (franc, yen, deutschmark, pound) -\n"; print "the default value is US dollars.\n\n"; print "Amount: "; while (&lt;STDIN&gt;) { ($amnt,$curr) = &amp;breakdown(chop($_)); $baseval = $amnt * (1/$rateof{$curr}); printf("%2.2f USD, ", $baseval * $rateof{'U'}); printf("%2.2f Franc, ", $baseval * $rateof{'F'}); printf("%2.2f DM, ", $baseval * $rateof{'D'}); printf("%2.2f Yen, and ", $baseval * $rateof{'Y'}); printf("%2.2f Pound\n\nAmount: ", $baseval * $rateof{'P'}); } sub breakdown { @line = split(" ", $_); $amnt = $line[0]; if ($#line == 1) { $curr = $line[1]; $curr =~ tr/a-z/A-Z/; # uppercase $curr = substr($curr, 0, 1); # first char only } else { $curr = "U"; } return ($amnt, $curr); } sub read_exchange_rate { open(EXCHRATES, " </code></pre> <p>Whenever it gets to line 17 (<code>$baseval = $amnt * (1/$rateof{$curr})</code>), I get the error <code>Illegal division by zero</code>.</p> <p>What's wrong?</p> <p>I am new to Perl, so please explain your answer.</p> <p>This only happens in Strawberry Perl. ActivePerl works, but it lists all the currency conversions as 0.0.</p> <p>UPDATE: I changed the code to look like this:</p> <pre><code>#!/usr/bin/perl &amp;read_exchange_rate; # read exchange rate into memory # now let's cycle, asking the user for input... print "Please enter the amount, appending the first letter of the name of\n"; print "the currency that you're using (franc, yen, deutschmark, pound) -\n"; print "the default value is US dollars.\n\n"; print "Amount: "; while (&lt;STDIN&gt;) { ($amnt,$curr) = &amp;breakdown(chomp($_)); $baseval = eval { $amnt * (1/$rateof{$curr}) }; printf("%2.2f USD, ", $baseval * $rateof{'U'}); printf("%2.2f Franc, ", $baseval * $rateof{'F'}); printf("%2.2f DM, ", $baseval * $rateof{'D'}); printf("%2.2f Yen, and ", $baseval * $rateof{'Y'}); printf("%2.2f Pound\n\nAmount: ", $baseval * $rateof{'P'}); } sub breakdown { @line = split(" ", $_); $amnt = $line[0]; if ($#line == 1) { $curr = $line[1]; $curr =~ tr/a-z/A-Z/; # uppercase $curr = substr($curr, 0, 1); # first char only } else { $curr = "U"; } return ($amnt, $curr); } sub read_exchange_rate { open EXCHRATES, "&lt;exchange.db" or die "$!\n"; while ( &lt;EXCHRATES&gt; ) { chomp; split; $curr = $_[0]; $val = $_[1]; $rateof{$curr} = $val; } close(EXCHRATES); } </code></pre> <p>Now, I'm getting this in Strawberry Perl when I use Open With(Yes, I'm on Windows): <code>No such file or directory</code> But if I double-click it, it starts fine, but the session looks kind of like this:</p> <pre><code>Please enter the amount, appending the first letter of the name of the currency that you're using (franc, yen, deutschmark, pound) - the default value is US dollars. Amount: 5 y 0.00 USD, 0.00 Franc, 0.00 DM, 0.00 Yen, and 0.00 Pound Amount: </code></pre> <p>Something is obviously wrong. I already changed all instances of <code>chop</code> to <code>chomp</code>. What do I do now?</p>
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    1. COWhen does that code from date from? It's really nasty-looking Perl4-style code. Far better Perl tutorials exist. See http://perl-tutorial.org/.
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    2. COThat isn't a tutorial. It is from SAMS Teach Yourself UNIX in 24 Hours. That code was written in 1999 for Perl 5. It was never meant to be a tutorial; it was just there as a example program.
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    3. COIf it's in a book called "Teach Yourself..." then, yes, it is a tutorial. Perl has moved on a lot in the fourteen years since that book was written. And it seems that the author wasn't particularly up to date even then as `chop()` went out of date in 1994. I really recommend that you throw that book away. You are unlikely to learn anything useful from it.
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