Your problem is that you're mixing up hashes (%hash) with hash references ({ key => value }) -- note the braces.

Replace the braces with parens and it should work: 

my %hash = ('perl' => 1 , 'C' => 0) ;

[download]
This produces a flat list, not a hashref, which is exactly what assignment to a hash wants.

Alternatively you could use a hashref (= a scalar pointing to a hash) everywhere: 

my $hash = {'perl' => 1 , 'C' => 0} ;
foreach my $key(sort keys %$hash)
{
     print "$key : $hash->{$key} \n" ;

        }

[download]

In reply to Re: printing hash produce errors by bart
in thread printing hash produce errors by Xfiles

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