import java.util.Scanner;
import java.lang.Math.*;
import java.text.DecimalFormat;

// Java program to calculate the volume of a sphere, cube or tetrahedron

class VolumeOfShapes {

	private static DecimalFormat df2 = new DecimalFormat("#.##");

	public static void main(String [] args) {

		Shape();

	}

	public static void Shape(){

		Scanner in = new Scanner(System.in);
		System.out.println("What shape would you like me to calculate the volume of?");
		String shape;
		shape = in.nextLine();

		switch(shape)
		{
			case "sphere":
				System.out.println("What is the radius of the sphere?");
				double radius = in.nextDouble();
				Sphere(radius);
				break;
			case "cube":
				System.out.println("What is the radius of the cube?");
				double width = in.nextDouble();
				Cube(width);
				break;
			case "tetrahedron":
				System.out.println("What is the radius of the tetrahedron?");
				double edge = in.nextDouble();
				Tetrahedron(edge);
				break;
			case "quit":
				break;
			default:
				System.out.println("Please enter 'sphere', 'cube' or 'tetrahedron' to continue. Enter 'quit' to exit program.");
				Shape();

		}

	}

	private static double Sphere(double radius){

		double x = (4.0/3.0);
		double y = (radius * radius * radius);
		double volume = (x * Math.PI) * y;
		System.out.println("Math.pi = " + Math.PI + "4/3 or x = " + x + "r squared or y = " + y + "volume = " + volume);
		System.out.println("The volume of this sphere with radius " + radius + " is " + df2.format(volume));
		return volume;

	}

	private static double Cube(double width){

		double volume = (width * width * width);
		System.out.println("The volume of this cube of width " + width + " is " + df2.format(volume));
		return volume;

	}

	private static void Tetrahedron(double edge){

		double a = (edge * edge * edge);
		double x = 6 * (Math.sqrt(2));
		double volume = a / x;
		System.out.println("The volume of this tetrahedron with edge " + edge + " is " + df2.format(volume));
		return volume;
	}

}