COP3337
Section U08
Fall 2015

                      EXAMPLES OF ARRAYS
                      ==================



i. The Program
--------------


import java.util.NoSuchElementException;
// exaple of arrays
public class TestArrays 
{

    public static void main(String[] args) 
    {
        System.out.println("Examples of Arrays");
        System.out.println("==================\n\n");
        
        // defining arrays
        double[] table = { 10.0, 20.5, -15.3, 17.8, 26.1, 
            5.1, -10.0};
        String[] friends = { "Pepe", "Angela", "Diana", "Rich",
            "Grandpa Smith"};
        double[] numbers = new double[0];
        short[] smallNumbers = new short[6];
        long[] largeNumbers;
        
        // show how length works
        System.out.println("The array table has " + table.length + 
                " numbers.");
        System.out.println("The array friends has " + friends.length + 
                " names.");
        
        // print the friends array
        printArray("The friends", friends);
        
        // test getIndex
        System.out.println("-15.3 occured in table at index " + getIndex(table, 
                -15.3));
        System.out.println("8.5 occured in table at index " + getIndex(table,
                8.5));
        System.out.println("Print the numbers in table greater than 8 and"
                + " smaller than 20\n");
        printInBetweenItems(table,8,20);
        
        System.out.println("The largest item in table is "
                + getLargest(table));
        
        System.out.println("We try to get the largest number in "
                + " the array numbers.");
        try
        {
            System.out.println(getLargest(numbers));
        }    
        catch (NoSuchElementException e)
        {
            System.out.println("We got a no such element exception.");
        }    
    }
    
    // some methods with arrays as parameters
    // print an array of strings
    public static void printArray(String arrayName, String[] arr)
    {
        // print the header
        System.out.println(arrayName);
        // underline it
        for (int i = 0; i < arrayName.length() ; i++)
            System.out.print("-");
        System.out.println();
        
        // check for empty array
        if (arr == null)
            System.out.println("The input array is null.");
        else if (arr.length == 0)
            System.out.println("The array is empty.");
        else // print it using an enhanced for loop
        {
            for (String current : arr)
                System.out.println(current);
        }
        System.out.println(); // print a separator line
    }        
    
    // return an index at which target occurs in 
    // double array arr
    // if target does not occur in arr, return -1
    public static int getIndex(double[] arr, double target)
    {
        final int NOT_FOUND = -1;
        // check if arr is empty
        if (arr == null || arr.length == 0)
            return NOT_FOUND;
        // search arr
        for (int i = 0; i < arr.length; i++ )
            if (arr[i] == target)
                return i;
        // target was not found
        return NOT_FOUND;        
    }
    
    // print all items of arr that are less than high and greater than low
    public static void printInBetweenItems(double[] arr, double low, double high)
    {
        if (arr == null || arr.length == 0)
            return; // there are no items in arr
        
        // print the qualifying numbers using an enhanced for loop
        for (double item: arr)
            if (item > low && item < high)
                System.out.println(item);
    }   
    
    // return the largest number in the double array arr
    public static double getLargest(double[] arr)
    {
        // check for empty array
        if (arr == null || arr.length == 0)
            throw new NoSuchElementException();
        
        // initialize largest 
        double largest = arr[0];
        for (int i = 1; i < arr.length; i++)
            // check if arr[i] is greater than largest
            if (arr[i] > largest)
                largest = arr[i];
        return largest;
    }        
}


ii. The output:
---------------


run:
Examples of Arrays
==================


The array table has 7 numbers.
The array friends has 5 names.
The friends
-----------
Pepe
Angela
Diana
Rich
Grandpa Smith

-15.3 occured in table at index 2
8.5 occured in table at index -1
Print the numbers in table greater than 8 and smaller than 20

10.0
17.8
The largest item in table is 26.1
We try to get the largest number in  the array numbers
We got a no such element exception.
BUILD SUCCESSFUL (total time: 0 seconds)