Re: Math error in Perl

[John Peacock]

Mark Berryman wrote:

Could someone please explain to me why only the last two expressions
return correct results?
$ perl -e "print (212-32)*5/9;"
180
$ perl -e "print (212-32)*5;"
180
$ perl -e "print (212-32);"
180
$ perl -e "print 5*(212-32)/9;"
100
There was just a long discussion on perl5porters about this.  You are 
implicitely calling print as a function in the first three cases, so you are 
effectively calling

	(print(212-32))*5/9;

to take just the first example.  Try this instead:

        $ perl -e "print +(212-32)*5/9;"
        100
If you had use '-w' you would have seen the warning

        $ perl -we "print (212-32)*5/9;"
        print (...) interpreted as function at -e line 1.
        Useless use of division (/) in void context at -e line 1.
        180
HTH

John

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John Peacock
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