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Thread: Help with Stringed Instrument Project

  1. #1
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    Default Help with Stringed Instrument Project

    Hello friends, I have been given the following assignment:


    Design and implement a stringed musical instrument class using the following guidelines:

    Data fields for your instrument should include number of strings, an array of string names representing string names (e.g. E,A,D,G), and boolean fields to determine if the instrument is tuned, and if the instrument is currently playing. You are welcome to add additional data fields if you like.
    A constructor method that set the tuned and currently playing fields to false.
    Other methods 1) to tune the instrument, 2) to start the instrument playing, and 3) to stop the instrument from playing.
    Other methods as you see fit (Add at least one unique method).
    Create a UML class diagram using a diagram tool (e.g. PPT, Visio) of your choice. Prepare the diagrams and place them in a word document along with a brief description of each of your classes.

    Create a Java class for your instrument. Be sure that your code matches your design specifications and some minimal functionality is included. For example, if you called the violin.play() method, you should at least print that the violin is playing. Similar functionality should be supplied when you stop playing, tune or call any of your methods. For example:

    public void playviolin() {
    System.out.println("The violin is now playing.");
    }

    Write the output from your Instrument class methods to a text file that a user entered from the command line arguments (e.g. java Mynamep3tst myfilename.txt). This allows your program to accept filenames from the user via a command line argument.

    Finally, create a Java test class that simulates using your instrument class. In your test class be you should at a minimum: a) Construct 10 instances of your instrument, b) tune your instruments, c) Start playing your instrument, d) Call your unique method, and e) Stop playing your instruments. (Hint: Arrays and Loops will make your job easier and result in more efficient code!)


    In my test file, named linwoodaraujop3.java I currently have:

    package linwoodaraujop3;
     
     
    public class LinwoodAraujop3 {  
     
        public static void main(String[] args) throws Exception  
        {  
     
            java.io.File file = new java.io.File("LinwoodAraujop3test.txt");  
     
            //check to see if file already exists  
            if (file.exists())  
            {  
                System.out.println("File already exists");    
                    System.exit(0);    
                }    
     
                //create a file    
                java.io.PrintWriter output = new java.io.PrintWriter(file);    
     
                //declare guitar object    
                Guitar guitar1 = new Guitar();    
     
                //write test results to file    
                output.println(guitar1.playGuitar());    
                output.println(guitar1.stopPlaying());    
                output.println(guitar1.tuneGuitar());    
            }  
    }
     
    class Guitar     
     {    
         boolean isTuned; //Guitar isn't tuned at the start   
         boolean isPlaying; //Guitar isn't playing at start    
     
         //array for strings on Guitar  
         char [] guitarStrings = {'E','A','D','G'};    
     
         //default Guitar object    
         public Guitar()    
         {    
             isTuned = false;    
             isPlaying = false;    
             System.out.println("The guitar isn't playing, and isn't tuned.");    
         }    
     
         public Guitar(boolean T, boolean P)    
         {    
             isTuned = T;    
             isPlaying = P;    
         }    
     
         public boolean playGuitar()    
         {    
            System.out.println("The guitar is playing!");    
            return isPlaying = true;    
         }    
     
         public boolean stopPlaying()    
         {    
             System.out.println("The guitar has stopped playing.");    
             return isPlaying = false;    
         }    
     
         public boolean tuneGuitar()    
         {    
             System.out.println("The guitar is being tuned!");    
             return isTuned = true;    
         }    
     
     }
    __________________________________________
    And for my instrument file I currently have:
    public class Guitar {
     
     
     public void main(String[] args){
     
            Guitar[] guitars;
     
           guitars = new Guitar[10]; 
     
                for(int i = 0; i < guitars.length; i++){
                   guitars[i] = new Guitar();
     
                }
     
     }
    }
    __________________________________________________ ___

    I have already cleaned up all of my code and currently am not receiving any error messages. However, when i run my programs it only prints to the console one iteration. And the file the it creates turns up with nothing inside of it. Any suggestions or help will be greatly appreciated.

    -Linwood


  2. #2
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    Default Re: Help with Stringed Instrument Project

    Why do you have 2 Guitar classes?

    Make sure you close the PrintWriter.
    Improving the world one idiot at a time!

  3. #3
    Super Moderator helloworld922's Avatar
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    Default Re: Help with Stringed Instrument Project

    Quote Originally Posted by Junky View Post
    Make sure you close the PrintWriter.
    Better yet, use try with resource constructs available in Java 7.

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