Because of this I thought that if a hash element has no value and it is used on an arithmetic operation then its default value is zero. Am I correct?

Yes, and this has not strictly to do with hash elements, but with any variable, be it a simple scalar or an element of an aggregate. One caveat though: under warnings, you will get a warning if you use such a value in a generic expression, but you won't if you use mutators instead:

tilde:~ [13:53:30]$ perl -we '$a=$a+1'
Use of uninitialized value in addition (+) at -e line 1.
tilde:~ [13:53:50]$ perl -we '$a+=1'
Name "main::a" used only once: possible typo at -e line 1.
tilde:~ [13:53:58]$ perl -we '$a++'
Name "main::a" used only once: possible typo at -e line 1.

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In reply to Re: Initialization of hash element.... by blazar
in thread Initialization of hash element.... by Chon-Ji

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