(PHP 4 = 4.0.5)
array_reduce() applies
iteratively the function
function to the elements of the array
input, so as to reduce the array to a single
value. If the optional
initial is available, it will be used at the
beginning of the process, or as a final result in case the
array is empty.
This will result in $b
containing 15,
$c containing 1200 (=
1*2*3*4*5*10), and $d containing 1.
See also array_filter() and
array_map().