use strict;
use warnings;

local $\ = "\n";

my %hash;

print '$hash{a} ',     ( $hash{a}            ) ? "true"    : "not true";
print '$hash{a} ',     ( defined $hash{a}    ) ? "defined" : "not defined";
print '$hash{a} ',     ( exists $hash{a}     ) ? "exists"  : "doesn't exist";
print "";

print '$hash{a}{b} ',  ( $hash{a}{b}         ) ? "true"    : "not true";
print '$hash{a}{b} ',  ( defined $hash{a}{b} ) ? "defined" : "not defined";
print '$hash{a}{b} ',  ( exists $hash{a}{b}  ) ? "exists"  : "doesn't exist";
print "";

print '$hash{a} ',     ( $hash{a}            ) ? "true"    : "not true";
print '$hash{a} ',     ( defined $hash{a}    ) ? "defined" : "not defined";
print '$hash{a} ',     ( exists $hash{a}     ) ? "exists"  : "doesn't exist";