If $arr1 holds the name of the array, you can step through the array with

foreach my $x (0..$#{$arr1})
{
  if($arr1->[$x] eq $1){$found++}
}
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IMO loops like this are better written as

foreach my $x (@$arr1)
{
  if ($x eq $1) {$found++}
}
[download]

You might read up on references and their use in References