in reply to simplish script (I think)

An array element is referenced using SQUARE brackets and a Dollar sigil.

You should be using 

    print "difference is " . $array[$counter] - $array[$counter - 1];

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Your second "foreach" is not necessary.
It can be replaced by: 
      print "difference is " . $array[$#array] - $array[-2] , "\n";

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See correction below

                "Imaginary friends are a sign of a mental disorder if they cause distress, including antisocial behavior. Religion frequently meets that description"

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Re^2: simplish script (I think)
by jeffenstein (Hermit) on Sep 25, 2020 at 08:10 UTC
    Your second "foreach" is not necessary.

    I think the OP is trying to do this with the second foreach:

    for(my $i=1; $i < @array; $i++){
    print "The difference is ", $array[$i] - $array[$i-1], "\n";
}

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[reply]
[d/l]
      You are correct(++) - I misread the curly brackets.

      Another way he can achieve this - arguably more readable is: 

      my @a=@array; # make a copy, since we will destroy @a
my $prev=pop @a; 
for (reverse @a){
   print  $prev - $_, "\n";
   $prev=$_;
}

      [download]

                      "Imaginary friends are a sign of a mental disorder if they cause distress, including antisocial behavior. Religion frequently meets that description"

[reply]
[d/l]

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