public static boolean isMasterCard ( String cc ) { int firstdig = Integer . parseInt ( cc . substring ( 0 , 1 ) ) ; int seconddig = Integer . parseInt ( cc . substring ( 1 , 2 ) ) ; if ( ( cc . length ( ) == 16 ) && ( firstdig == 5 ) && ( ( seconddig >= 1 ) && ( seconddig <= 5 ) ) ) return isCreditCard ( cc ) ; return false ; }
Checks to see if the cc number is a valid Master Card number