Write a program to play a song represented as text. In Eclipse, create a package

Question

Write a program to play a song represented as text. In Eclipse, create a package called program2 (note the lowercase first letter), in which you will create a program called PlaySimpleSong.

Write the program so that it:

declares and creates a symbol table using the algs31.BinarySearchST class;

reads in a file notes_frequencies.txt where each line is a pair of strings separated by whitespace. The first string is the name of a musical note and the second its sound frequency as found on a piano. For example, the note A4 is paired with the frequency 440Hz and the note C4 with the frequency 261.626Hz. As each line is read, an entry is made in the symbol table where the note name is the key and the frequency is the value.

reads in a song file, where each line contains a note name and a duration in seconds, separated by whitespace. A sample file is sample_simple_song.txt, which plays every C for half a second. Another song you might try is lotr.txt. Looking up the frequency corresponding to the note name, the program calls the method below to play the note.

Both the notes and frequencies file and the song file should be placed into the Eclipse data directory and, as in the GPA program, read in using StdIn and the fromFilemethod.

To process a text file where each line contains a fixed set of data fields:

use the method readLine in the StdIn class, which returns a string;

split the string into an array of strings using the instance method split in the String class;

convert the numeric strings into numeric values using the method parseDouble in the Double class.

To play each note, place into your program and call this method:

You will also have to import stdlib.StdAudio: http://introcs.cs.princeton.edu/java/stdlib/javadoc/StdAudio.html

sample_simple_song.txt

notes_frequencies.txt

A0   27.5
A#0     29.1353
B0   30.8677
C1   32.7032
C#1     34.6479
D1   36.7081
D#1     38.8909
E1   41.2035
F1   43.6536
F#1     46.2493
G1   48.9995
G#1     51.913A1   55
A#1     58.2705
B1   61.7354
C2   65.4064
C#2     69.2957
D2   73.4162
D#2     77.7817
E2   82.4069
F2   87.3071
F#2     92.4986
G2   97.9989
G#2     103.826
A2   110
A#2     116.541
B2   123.471
C3   130.813
C#3     138.591
D3   146.832
D#3     155.563
E3   164.814
F3   174.614
F#3     184.997
G3   195.998
G#3     207.652
A3   220
A#3     233.082
B3   246.942
C4   261.626
C#4     277.183
D4   293.665
D#4     311.127
E4   329.628
F4   349.228
F#4     369.994
G4   391.995
G#4     415.305
A4   440
A#4     466.164
B4   493.883
C5   523.251
C#5     554.365
D5   587.33
D#5     622.254
E5   659.255
F5   698.456
F#5     739.989
G5   783.991
G#5     830.609
A5   880
A#5     932.328
B5   987.767
C6   1046.5
C#6     1108.73
D6   1174.66
D#6     1244.51
E6   1318.51
F6   1396.91
F#6     1479.98
G6   1567.98
G#6     1661.22
A6   1760
A#6     1864.66
B6   1975.53
C7   2093
C#7     2217.46
D7   2349.32
D#7     2489.02
E7   2637.02
F7   2793.83
F#7     2959.96
G7   3135.96
G#7     3322.44
A7   3520
A#7     3729.31
B7   3951.07
C8   4186.01

Explanation / Answer

Please find Below the main class to play the tone based on input song file and given frequency file:

PlaySimpleSong.java

package program2;

import java.io.File;

import java.io.FileNotFoundException;

import java.util.Scanner;

public class PlaySimpleSong {

public static void main(String[] args) throws FileNotFoundException {

//Create two scanner objects two handle two files

Scanner scan=new Scanner(new File("sample_simple_song.txt"));

Scanner scan2=new Scanner(new File("notes_frequencies.txt"));

StdIn.setScanner(scan);

//Read all lines from input sample song file

String[] notes=StdIn.readAllLines();

//Loop through all lines of sample song file

for (String string : notes) {

//Split the string

String[] lines=string.split(" ");

String note=lines[0];

//Convert duration to double

Double duration=Double.parseDouble(lines[1]);

//Set Stdin object to point to other file

StdIn.setScanner(scan2);

//Loop through notes_frequency file until End of File

while(StdIn.hasNextLine())

{

//Read the Line

String line=StdIn.readLine();

//Split the line

String[] frequencyLines=line.split(" ");

//if the note matches the input note then call the playTone method

if(note.equals(frequencyLines[0])){

String tone=frequencyLines[1];

//Convert frequency to double

Double frequency=Double.parseDouble(frequencyLines[1]);

playTone(frequency, duration);

break;

}

}

}

}

//Method to play the tone

public static void playTone(double frequency, double duration) {

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);

}

}

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.