driver code
$ mat = array ( array ( 1 , 2 , 3 , 4 , 5 ) , array ( 5 , 3 , 5 , 4 , 0 ) , array ( 5 , 6 , 7 , 8 , 9 ) , array ( 0 , 6 , 3 , 4 , 12 ) , array ( 9 , 7 , 12 , 4 , 3 ) ) ; echo " Max ▁ difference ▁ : ▁ " . colMaxDiff ( $ mat ) . " STRNEWLINE " ;