import java.util.Scanner;
import java.io.IOException;

/**
 A user interface for calculating the area of a Triangle

 This user interface doesn't "do" the calculation of the area.
 The knoweldge of how to "do" the calculation is embedded in the Triangle
 class (i.e. the Model class.)

 @author Phill Conrad
 @version 2011.01.01
 @see <a href="http://en.wikipedia.org/wiki/You_ain't_gonna_need_it">Wikipedia article on YAGNI</a>

*/

public class TriangleConsoleUI {

    public static double argToDouble(String arg) {
	try {
	    return Double.parseDouble(arg);
	} catch (NumberFormatException nfe) {
	    System.err.println("Sorry: " + 
			       arg + " could not be interpreted as a number. Please try again");
	    System.exit(1);
	}
	return 0.0; // unreachable, but needed to satisfy compiler
    }

    public static void main(String [] args)
    {
	Scanner s = new Scanner(System.in);

	double base,height;
	if (args.length == 2) {
	    base = argToDouble(args[0]);
	    height = argToDouble(args[1]);
	} else {
		System.out.print("Please enter base of Triangle: ");
		base = argToDouble(s.nextLine());
		System.out.print("Please enter height of Triangle: ");
		height = argToDouble(s.nextLine());
	}
	 
	Triangle t = new Triangle(base,height);
	System.out.println("Area = " + t.getArea());
	
    }

} // class Triangle