Chemistry.java

import java.util.Arrays;
import java.util.Scanner;


public class Chemistry
{
	static Scanner console = new Scanner(System.in);
	public static void main(String[] args)
	{
		for(;;)
		{
			System.out.print(">> ");
			String str = console.nextLine();
			String[] a = str.split(",");
			System.out.println(Arrays.toString(a));
			try
			{
				String mode = a[0];
				double[] d = {Double.parseDouble(a[1]),Double.parseDouble(a[2])};
				System.out.print("\n");
				
				
				if(mode.equals("w2e"))
				{
					System.out.println(wavelengthToEnergy( f(d[0],d[1]) ));
				}
				else if(mode.equals("w2f"))
				{
					System.out.println(wavelengthToFrequency( f(d[0],d[1]) ));
				}
				else if(mode.equals("f2e"))
				{
					System.out.println(frequencyToEnergy( f(d[0],d[1]) ));
				}
			}
			catch(Exception e)
			{
				e.printStackTrace();
			}
		}
	}
	
	public static final double c = (3.0)*(double)Math.pow(10,8); //Speed of light
	public static final double h = (6.626)*(double)Math.pow(10,-34); //Plank's constant
	
	public static double f(double dec, double exp)
	{
		return (dec)*(double)Math.pow(10,exp);
	}
	
	public static double wavelengthToEnergy(double w)
	{
		return frequencyToEnergy(wavelengthToFrequency(w));
	}
	public static double wavelengthToFrequency(double w)
	{
		return c/w;
	}
	public static double frequencyToEnergy(double f)
	{
		return f*h;
	}
}