my ($low,$high) = (0,scalar(@$array));  # computes the length of the a
+rray and gives it to $high
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You have an off-by-one error.    The value scalar(@$array) is not a valid index to any of the values in @$array.

my ($low,$high) = (0,$#$array);  # computes the length of the array an
+d gives it to $high
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