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Re: expected 0 not result gotten

by quester (Vicar)
on Dec 22, 2011 at 06:40 UTC ( #944728=note: print w/ replies, xml ) Need Help??


in reply to expected 0 not result gotten

To answer the second part of your question:

Digging into this I tried something "simplier" and got more confused:

perl -e 'print ((.0425*2) + .0025 ) - ((.0425*2) + .0025 ); print $/;'

just bring the perlrun option -w (warnings) to the rescue:

$ perl -we 'print ((.0425*2) + .0025 ) - ((.0425*2) + .0025 ); print $ +/;' print (...) interpreted as function at -e line 1. Useless use of subtraction (-) in void context at -e line 1. 0.0875

That can be fixed with either extra parens or a plus sign:

$ perl -we 'print (((.0425*2) + .0025 ) - ((.0425*2) + .0025 )); print + $/;' 0 $ perl -we 'print +((.0425*2) + .0025 ) - ((.0425*2) + .0025 ); print +$/;' 0

There is a explanation of this in the perldoc for print:

"Be careful not to follow the print keyword with a left parenthesis unless you want the corresponding right parenthesis to terminate the arguments to the print; put parentheses around all arguments (or interpose a + , but that doesn't look as good)."


Comment on Re: expected 0 not result gotten
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Re^2: expected 0 not result gotten
by Anonymous Monk on Dec 27, 2011 at 09:27 UTC
    surprising but true, i get something like, $ perl -we 'my $x = (.0425 * 2) + .0025; print $x - (.042+5 * 2) - .0025, $/;' -9.957 i am using perl 5.8.8

      Do you mean that it surprises you that

      .0425*2
      

      is different than

      .042+5*2
      

      Um... wow... really?

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