import java.text.DecimalFormat;

/**
 * Exercise 5.7 p 156<br>
 * Each of these method is an attempt to compute the average of 3 integers as
 * accurately as possible. None of them is correct. There are syntax and logical
 * errors. Find the error(s) in each one of them.<br>
 * Complete also the last method to display a number of hours as hours, minutes
 * and seconds.
 */

public class Exercise57 {
	public double average3A(int n1, int n2, int n3) {
		// only n3 is divided by 3
		// return (double) n1 + (double) n2 + (double) n3 / 3.0;
		// fix: add parentheses around (double)n1 +... + (double)n3
		return ((double) n1 + (double) n2 + (double) n3) / 3.0;

	}

	public double average3B(int n1, int n2, int n3) {
		double result;
		// don't use new to initialize a double (double is a primitive type)
		// result = new ((n1+n2+n3)/3.0);
		// fix: remove new
		result = ((n1 + n2 + n3) / 3.0);
		return result;
	}

	public double average3C(int n1, int n2, int n3) {
		double result;
		// one extra right parenthesis. Fix remove the extra parenthesis
		// result = (double)(n1+n2+n3)/3.0);
		result = (double) (n1 + n2 + n3) / 3.0;
		return result;
	}

	public double average3D(int n1, int n2, int n3) {
		// a cast is written as (double) and not just double
		// fix: write all of the casts in parentheses
		// return (double(n1)+double(n2)+double(n3))/3;
		return ((double) (n1) + (double) (n2) + (double) (n3)) / 3;
	}

	/**
	 * Extra pratice: display a number of hours as hh:mm:ss
	 */
	public void printAsHMS(double hours) {
		int h = (int) hours;
		// what is left
		hours -= h; // same as hours = hours - h;
		int m = (int) (hours * 60);
		// what is left
		hours -= m / 60.0;
		int s = Math.round((float) (hours * 3600)); // cast to a float so that
		// round returns an int and not a long
		DecimalFormat df = new DecimalFormat("00");
		System.out.println(df.format(h) + ":" + df.format(m) + ":"
				+ df.format(s));
	}

	/**
	 * To test
	 */
	public static void main(String[] args) {
		Exercise57 e = new Exercise57();
		int n1 = 2, n2 = 3, n3 = 5; // average = (2 + 3 + 4) / 3 = 10/3 = 3.33
		System.out.println("average 3A = " + e.average3A(n1, n2, n3));
		System.out.println("average 3B = " + e.average3B(n1, n2, n3));
		System.out.println("average 3C = " + e.average3C(n1, n2, n3));
		System.out.println("average 3D = " + e.average3D(n1, n2, n3));
		// 1 hour 10 minutes 17 seconds
		double hours = 1 + 10.0 / 60.0 + 17.0 / 3600.0;
		e.printAsHMS(hours);
	}
}