Question

Java Programming:

Write a class called GNotes that:

- plays in order the notes G4, G5, G6, each for one and a half seconds

- The frequency of G4 is 392 Hz. Look up the other two.

Answer 1

import java.util.HashMap;

import stdlib.StdAudio;

public class GNotes {

    public static void main(String[] args) {
        HashMap<String, Double> frequencies = new HashMap<>();
        frequencies.put("G4", 391.995);
        frequencies.put("G5", 783.991);
        frequencies.put("G6", 1567.98);

        playNote(1.5, frequencies.get("G4"));
        playNote(1.5, frequencies.get("G5"));
        playNote(1.5, frequencies.get("G6"));
    }

    public static void playNote(double duration, double frequency) {
        final int sliceCount = (int) (StdAudio.SAMPLE_RATE * duration);
        final double[] slices = new double[sliceCount+1];
        for (int i = 0; i <= sliceCount; i++) {
            slices[i] += Math.sin(2 * Math.PI * i * frequency / StdAudio.SAMPLE_RATE);
        }
        StdAudio.play(slices);
    }

}

In case of any doubts, please ask in comments. If the answer helps you, please upvote. I am in great need of upvotes. Thanks!