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Do you know where your variables are?

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Hi Monks,

I ran below code with use integer line commented and uncommented.

#!/usr/bin/perl #use integer; my $max_neg_num=((2**32)-1); print "\nmax neg num is $max_neg_num\n"; $error=4294967263 -$max_neg_num-1; print "error is $error \n";

With use integer commented: max neg num is 4294967295 error is -33

With use integer uncommented. max neg num is -2 error is -32

When I looked at integer pragma documentation, it says numbers are wrapped around after largest +ve number i.e. 2^31-1. By that logic max neg number should be -1 represented by 2^32-1.

Also, I am surprised that without integer pragma, how come I am able to see the results correctly even though it is 32 bit machine? I think its a naive question, but I am afraid I will remain naive if I dont ask it. I would like to know how such arithmetic is handled on 32 bit machines. Is there a potability issue if I write the code as above with use integer commented?

Please enlighten me!!

In reply to Question on simple arithmetic using perl by perlbaski

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