I don't like leaving the $pointer variable grow indefinitely.
This code is equivalent, but keeps $pointer in [0,@buffer). In fact, just gets the remainder after each $pointer change 
my @buffer = (0) x 5;
my $pointer = 0;
for (0..30) {
    print "old value: ", $buffer[$pointer], "\n";
    print "new value: $_\n";
    $buffer[$pointer] = $_; 
    $pointer = (++$pointer) % @buffer;
}

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In reply to Re^2: Circular buffer by mellon85
in thread Circular buffer by Anonymous Monk

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