import java.text.DecimalFormat; // for formatting

/**
 * A class to illustrate the use of a 2D array.<br>
 * The methods of the class initialize a 2D array, namely an array to store the
 * daily rainfall amount over 3 months. The monthly rainfall average is
 * computed.
 */

public class TwoDimensionalArray {
	
	public static void main(String[] args) {
		new TwoDimensionalArray().processRainfall();
	}

	/**
	 * Initialize a 2D array to store the daily rainfall over a 3 months period
	 * (namely April, May and June). Do initialization in a private method
	 * (assign to each element a random double between 0 and 10).<br>
	 * Then, compute and print the monthly rainfall average.
	 */
	public void processRainfall() {
		// Store in an array the daily rainfall
		// over a period of 3 months (April, May, June)
		// rainfall should be an array of 3 1D arrays (each 1D array
		// is of size 30, 31 and 30).
		double[][] rainfall = new double[3][];
		rainfall[0] = new double[30]; // April
		rainfall[1] = new double[31]; // May
		rainfall[2] = new double[30]; // June

		// Initialize the array
		// (call fillRandomly)
		fillRandomly(rainfall);
		
		/*
		// side point: don't use a for each loop to 
		// initialize an array
		// example with a 1D array
		double[] b = new double[20];
		for(double val: b) {
			val = Math.random();
		}
		// not the same as 
		for (int i = 0; i < b.length; i ++) {
			b[i] = Math.random();
		}
		*/

		// Compute and print the average rainfall for each month
		// (call computeAndPrintMonthlyAverage)
		computeAndPrintMonthlyAverage(rainfall);
	}

	/**
	 * Initialize the elements of a 2D array with a random double between 0 and
	 * 10.
	 * 
	 * @param rainfall
	 *            the array to initialize
	 */
	private void fillRandomly(double[][] rainfall) {
		// Fill randomly the array with a random value between 0 and 10
		for (int i = 0; i < rainfall.length; i 	++) {
			for (int j = 0; j < rainfall[i].length; j ++) {
				rainfall[i][j] = 10 * Math.random();
			}
		}
	}

	/**
	 * Compute and print the average daily rainfall for each month
	 * 
	 * @param rainfall
	 *            the array to average
	 */
	private void computeAndPrintMonthlyAverage(double[][] rainfall) {
		DecimalFormat df = new DecimalFormat("0.00");
//		String[] month = new String[3];
//		month[0] = "April";
//		month[1] = "May";
//		month[2] = "June";
		// Better here to write
		String[] month = {"April", "May", "June"};
		int index = 0;
		for (double[] row: rainfall) {
			double sum = 0;
			for (double value: row) {
				sum += value;
			}
			System.out.println(
					"The daily average rainfall for the month of " + 
			         month[index] + " is " +
			df.format(sum/row.length));
			index ++;
		}
	}
}