1    /* 
2     * A program that lists and prints prime arrays 
3     * and their lengths. 
4     * Questions: 
5     * a) int[] AnArray; 
6     * b) int[] AnArray = new int[#]; 
7     * c) primes[#] 
8     */
9    package arrayplay;
10   
11   public class Primes {
12       public static void main(String[] args) {
13           int[] primes = new int[4];
14   
15           primes[0] = 2;
16           primes[1] = 3;
17           primes[2] = 5;
18           primes[3] = 7;
19   
20           System.out.println("length of primes array = " + primes.length);
21           System.out.println("first prime = " + primes[0]);
22           System.out.println("last prime = " + primes[3]);
23           System.out.println("last prime = " + primes[primes.length-1]);
24   
25           System.out.println("\nThe initial array ...");
26           int i = 0;
27           while (i < primes.length) {
28               System.out.println(primes[i]);
29               i = i + 1;
30           }
31           int temp = primes[0];
32           primes[0] = primes[primes.length-1];
33           primes[primes.length-1] = temp;
34   
35           System.out.println("\nThe final array ...");
36           for (int x = 0; x < primes.length; x = x + 1) {
37               System.out.println(primes[x]);
38           }
39       }
40   }
41