Question: How do you give functions private variables that retain their values between calls?
Answer: Create a scope surrounding that sub that contains lexicals. Only lexical variables are truly private, and they will persist even when their block exits if something still cares about them. Thus: { my $i = 0; sub next_i { $i++ } sub last_i { --$i } } creates two functions that share a private variable. The $i variable will not be deallocated when its block goes away because next_i and last_i need to be able to access it.
Question:
How do you give functions private variables that retain their values between calls? Answer:
Create a scope surrounding that sub that contains lexicals. Only lexical variables are truly private, and they will persist even when their block exits if something still cares about them. Thus: { my $i = 0; sub next_i { $i++ } sub last_i { --$i } } creates two functions that share a private variable. The $i variable will not be deallocated when its block goes away because next_i and last_i need to be able to access it. Source: CoolInterview.com
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