/**Prints the frequencies in Hz of all the notes in the western scale,
 * in the range of human hearing. */
public class NoteFreqPrinter
{
	public static void main(String[] args)
	{
		String[] noteNames = {"A", "A#", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#"};
		//the ratio between adjacent notes in equal temperament:
		//these values are interchangeable
		double ratio = Math.pow(2, 1.0/12.0);//calculated by java, or
		double wikiRatio = 1.059463094359295264561825;//borrowed from wikipedia's page on equal temperament
		
		int numFreqs = 24;//how many notes to print. Recalculated later
		int octave = 55;//the frequency (note) to start at. 55Hz is A1.
		
		//human hearing is between 20Hz and 20KHz;
		//calculate how many notes we'll need, to determine size of array
		while(octave < 20000)
		{
			octave *= 2;
			numFreqs += 12;
		}
		numFreqs -= 5;//cheap fix to discard inaudible notes in last octave
		double[] freqs = new double[numFreqs];
		
		//these values are very close, but might differ slightly due to precision
		System.out.println("derived ratio value  : "+ratio);
		System.out.println("wikipedia ratio value: "+wikiRatio);
		
		freqs[0] = 13.75; // the first and lowest note: A-1
		
		System.out.print(noteNames[0]+": ");
		System.out.print(freqs[0]+"\n");
		
		for(int i = 1; i < freqs.length; i++)
		{
			freqs[i] = freqs[i-1] * ratio;
			if(((i % 12) == 0)//if note should have an integral frequency
			&& (i > 12))// (octaves of A),
			{// cast it to an int to discard precision loss 
				freqs[i] = Math.round(freqs[i]);
			}
			
			System.out.print(noteNames[i%12]+": ");
			System.out.print(freqs[i]+"\n");
		}
	}
}