CIS 260 TestArrays.java

Code

/*
    TestArrays.java
    CIS 260
    2/16/2005
    David Klick

    Demonstrates various methods of the Arrays and Collections
    classes.
*/

import java.util.*;

public class TestArrays {
    public static void main(String[] args) {
        int pos;
        Integer[] a1 = { new Integer(78), new Integer(10), new Integer(-3),
            new Integer(9), new Integer(17), new Integer(88),
            new Integer(29), new Integer(32), new Integer(31),
            new Integer(-4) };
        Integer[] a2 = new Integer[a1.length];
        Integer[] a3 = new Integer[a1.length];

        System.arraycopy(a1, 0, a2, 0, a1.length);
        Arrays.fill(a3, 16);
        System.out.println("a1: " + Arrays.toString(a1));
        System.out.println("a2: " + Arrays.toString(a2));
        System.out.println("a3: " + Arrays.toString(a3));

        if (Arrays.equals(a1, a2)) {
            System.out.println("a1 and a2 are equal");
        } else {
            System.out.println("a1 and a2 are not equal");
        }

        if (Arrays.equals(a1, a3)) {
            System.out.println("a1 and a3 are equal");
        } else {
            System.out.println("a1 and a3 are not equal");
        }

        // new generics notation restricts contents of List
        List<Integer> lst = new ArrayList<Integer>(Arrays.asList(a1));
        System.out.println("a1 max: " + Collections.max(lst));
        System.out.println("a1 min: " + Collections.min(lst));
        Collections.sort(lst);
        lst.toArray(a1);
        System.out.println("This list should be in sorted order:");
        System.out.println("a1: " + Arrays.toString(a1));


        pos = Arrays.binarySearch(a1, 88);
        if (pos > -1) {
            System.out.println("88 found in a1 at position " + pos);
        } else {
            System.out.println("88 not found in a1");
        }

        pos = Arrays.binarySearch(a1, -4);
        if (pos > -1) {
            System.out.println("-4 found in a1 at position " + pos);
        } else {
            System.out.println("-4 not found in a1 at position " + pos);
        }

        pos = Arrays.binarySearch(a1, 70);
        if (pos > -1) {
            System.out.println("70 found in a1 at postion " + pos);
        } else {
            System.out.println("70 not found in a1");
        }

        Collections.reverse(lst);
        System.out.println("The list should now be reversed");
        System.out.println("a1 reversed: " + Arrays.toString(lst.toArray()));
        Collections.shuffle(lst);
        System.out.println("The list should now be shuffled");
        System.out.println("a1 shuffled: " + Arrays.toString(lst.toArray()));
    }
}

/*
    Sample output:

    a1: [78, 10, -3, 9, 17, 88, 29, 32, 31, -4]
    a2: [78, 10, -3, 9, 17, 88, 29, 32, 31, -4]
    a3: [16, 16, 16, 16, 16, 16, 16, 16, 16, 16]
    a1 and a2 are equal
    a1 and a3 are not equal
    a1 max: 88
    a1 min: -4
    This list should be in sorted order:
    a1: [-4, -3, 9, 10, 17, 29, 31, 32, 78, 88]
    88 found in a1 at position 9
    -4 found in a1 at position 0
    70 not found in a1
    The list should now be reversed
    a1 reversed: [88, 78, 32, 31, 29, 17, 10, 9, -3, -4]
    The list should now be shuffled
    a1 shuffled: [88, 31, 29, 78, -4, 17, 32, 9, -3, 10]
*/