// Example 20 from page 17 of Java Precisely second edition (The MIT Press 2005) // Author: Peter Sestoft (sestoft@itu.dk) class Example20 { public static void main(String[] args) { System.out.println("August 31 is legal: " + checkdate(8, 31)); System.out.println("April 31 is legal: " + checkdate(4, 31)); } static int[] days = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; static boolean checkdate(int mth, int day) { return (mth >= 1) && (mth <= 12) && (day >= 1) && (day <= days[mth-1]); } }