PlayThatTuneExtended

/*************************************************************************
 *  Compilation:  javac PlayThatTune.java
 *  Execution:    java PlayThatTune < data.txt
 *  Dependencies: StandardLib, found at http://introcs.cs.princeton.edu/java/stdlib/stdlib.jar
 *
 *  % java PlayThatTune < testaudio.txt
 *
 *
 *  Make sure amplitudes for each line add up to exactly 1
 *  Make sure lengths for each note on the same line are the same #
 *  Data files format:
 *
 *  note length amplitude note length amplitude...
 *  1    .5      .1         5    .5     .9
 *
 *
 *
 *************************************************************************/

public class PlayThatTune
{
    public static double[] sum(double[] a, double[] b,
                                    double awt, double bwt)
    { // superpose a and b, weighted.
        double[] c = new double[a.length];
        assert (a.length == b.length);
        for (int i = 0; i < a.length; i++)
            c[i] = a[i]*awt + b[i]*bwt;
        return c;
    }

    public static double[] tone(double hz, double duration, double amplitude)
    {
        int N = (int) (StdAudio.SAMPLE_RATE * duration);
        double[] a = new double[N+1];
            for (int i = 0; i <= N; i++) {
            a[i] = amplitude * Math.sin(2 * Math.PI * i * hz / StdAudio.SAMPLE_RATE);
        }
        return a;
    }

    public static double[] note(int p, double t, double amplitude)
    { //Play note p, with harmonics.
        double hz = 440.0 * Math.pow(2, p/12.0);
        double[] a = tone(hz, t, amplitude);
        double[] hi = tone(2*hz, t, amplitude);
        double[] lo = tone(hz/2, t, amplitude);
        double[] h = sum(hi, lo, .5, .5);
        return sum(a, h , .5, .5);
    }

    public static void playmore(int iter, double[] bj, String[] z)
    {
        //iterate with int iter backwards through z
        int pitch = Integer.parseInt(z[(iter*3)-3]);
        double duration = Double.parseDouble(z[(iter*3)-2]);
        double amplitude = Double.parseDouble(z[(iter*3)-1]);
        //Check amplitude value
        assert (amplitude < 1 && amplitude > 0);
        double[] a = note(pitch, duration, amplitude);
        System.out.println(a.length + " is a[]");
        System.out.println(bj.length + " is bj[]");
        iter -= 1;
        for (int i = a.length-1; i >= 0; i--)
        {
            //iterate over a[] backwards, adding a[i] to bj[i]
            //System.out.println("yes"+i);
            bj[i] = (bj[i] + a[i]);
        }
        if (iter == 0)
        {
            StdAudio.play(bj);
        }
        else
        {
            playmore(iter, bj, z);
        }
    }

    public static void play()
    {
        String[] z = StdIn.readLine().split(" ");
        int zphi = z.length;
        if (zphi == 1) return;
        if (zphi > 3)
        {
            System.out.println(zphi);
            double duration = Double.parseDouble(z[1]);
            int N = (int) (StdAudio.SAMPLE_RATE * duration);
            double[] bj = new double[N+1];
            playmore((zphi)/3, bj, z);
            return;
        }
        for (int i = 0; i <= z.length-1; i++)
        {
            System.out.println(z[i]);
        }
        int pitch = Integer.parseInt(z[0]);
        double duration = Double.parseDouble(z[1]);
        double[] a = note(pitch, duration, 1);
        //System.out.println(a.length-1);
        StdAudio.play(a);
    }

    public static void main(String[] args)
    { //Read and play a tune with harmonics
        while (!StdIn.isEmpty())
        { // Read and play a note with harmonics.
            play();
        }
    }
}