Wrong coding

[Craig E. Lewis]

class DrumKit {

 boolean tophat = true;
 boolean snare = true;

 void playTopHat() {
   System.out.println( "ding ding da-ding");
 }
 void playSnare() {
   System.out.println("bang bang ba-bang");
 }
}
class DrumKitTestDrive {
  public static void main(String [] args) {
     Drumkit d = new Drumkit();
     d.playsnare();
     d.snare = false;
     d.playTopHat();
      
     if (d.snare == true) {
       d.playsnare();
     }
   }
}

can anybody tell me whats wrong with this as well as what is?
boolean
=false
=true
mean

Added Code tags, please read UseCodeTags

[Mohamed Sanaulla]

What is the issue you are facing?

And

if ( something == true)
{
}

can be written as

if ( something)
{
}

[Winston Gutkowski]

Craig E. Lewis wrote:can anybody tell me whats wrong with this as well as what is?

Well if you told us what the matter is it would help.

Second (and I'll say this before Campbell does)
if (d.snare == true) {
is redundant, and prone to error (although not incorrect logically). All you need is
if (d.snare) {

Winston

[Edit] Too slow

[Craig E. Lewis]

This is the problem

C:\Users\Craig\java\src>javac Drumkit.java
.\Drumkit.java:1: duplicate class: DrumKit
class DrumKit {
^
.\Drumkit.java:14: duplicate class: DrumKitTestDrive
class DrumKitTestDrive {
^
Drumkit.java:17: cannot access Drumkit
bad class file: .\Drumkit.java
file does not contain class Drumkit
Please remove or make sure it appears in the correct subdirectory of the classpa
th.
Drumkit d = new Drumkit();
^
3 errors

C:\Users\Craig\java\src>

[Winston Gutkowski]

Craig E. Lewis wrote:This is the problem

C:\Users\Craig\java\src>javac Drumkit.java
.\Drumkit.java:1: duplicate class: DrumKit
class DrumKit {
^
.\Drumkit.java:14: duplicate class: DrumKitTestDrive

Well the message is quite explicit; although it may have something to do with the fact that your DrumKit class isn't public.

My suggestion: Add public to the definition, and remove the DrumKitTestDrive class altogether. It doesn't add anything, and since it's not public, the main() method will never be run anyway.

Winston

[Jesper de Jong]

Also note that DrumKit is not the same as Drumkit. Java is case-sensitive.

[Winston Gutkowski]

Jesper de Jong wrote:Also note that DrumKit is not the same as Drumkit. Java is case-sensitive.

Well spotted that man. Totally missed it.

Winston

[Craig E. Lewis]

Hey Guys I have a new problem thanks for solving the last
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.


DrumKit.java:18: cannot find symbol
symbol : method playsnare()
location: class DrumKit
d.playsnare();
^
DrumKit.java:23: cannot find symbol
symbol : method playsnare()
location: class DrumKit
d.playsnare();
^

I also changed the coding
public class DrumKit {

boolean tophat = true;
boolean snare = true;

void playTopHat() {
System.out.println( "ding ding da-ding");
}
void playSnare() {
System.out.println("bang bang ba-bang");
}
}

class DrumKitTestDrive {
public static void main(String [] args) {

     DrumKit d = new DrumKit();
     d.playsnare();
     d.snare = false;
     d.playTopHat();
      
     if (d.snare == true) {
      d.playsnare();
      }
      }
      }

2 errors

[Craig E. Lewis]

Sorry guys ignore the last thing i said i solved it and have compiled it but i don't understand this

C:\Users\Craig\java>java DrumKit
Exception in thread "main" java.lang.NoSuchMethodError: main

This is what i did to the code on your suggestion i took drumkit testdrive



public class DrumKit {

boolean tophat = true;
boolean snare = true;

void playTopHat() {
System.out.println( "ding ding da-ding");
}
void playSnare() {
System.out.println("bang bang ba-bang");
}
}

[Henry Wong]

Craig E. Lewis wrote:Hey Guys I have a new problem thanks for solving the last
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.


DrumKit.java:18: cannot find symbol
symbol : method playsnare()
location: class DrumKit
d.playsnare();
^
DrumKit.java:23: cannot find symbol
symbol : method playsnare()
location: class DrumKit
d.playsnare();
^

I also changed the coding

public class DrumKit {

 boolean tophat = true;
 boolean snare = true;

 void playTopHat() {
   System.out.println( "ding ding da-ding");
   }
 void playSnare() {
   System.out.println("bang bang ba-bang");
   }
   }

   class DrumKitTestDrive {
     public static void main(String [] args) {

     DrumKit d = new DrumKit();
     d.playsnare();
     d.snare = false;
     d.playTopHat();
      
     if (d.snare == true) {
      d.playsnare();
      }
      }
      }

2 errors

As already mentioned, Java is case-sensitive. This is also true for the method names.

Henry

[Henry Wong]

Craig E. Lewis wrote:Sorry guys ignore the last thing i said i solved it and have compiled it but i don't understand this

C:\Users\Craig\java>java DrumKit
Exception in thread "main" java.lang.NoSuchMethodError: main

This is what i did to the code on your suggestion i took drumkit testdrive

public class DrumKit {

 boolean tophat = true;
 boolean snare = true;

 void playTopHat() {
   System.out.println( "ding ding da-ding");
   }
 void playSnare() {
   System.out.println("bang bang ba-bang");
   }
   }

The compiler is complaining that the DrumKit class doesn't have a main() method. Question. Does your DrumKit class have a main method?

Henry

[Craig E. Lewis]

I have just started and i am not sure what you mean

[Jesper de Jong]

Do you know what the main() method is? When you run a Java program, the Java runtime environment looks for a method public static void main(String[] args) in the class that you are trying to run.

You are trying to run class DrumKit, but it does not have a main() method. In fact, the main() method is in one of the other classes you wrote. You have to run that other class, not the DrumKit class.

[Winston Gutkowski]

Jesper de Jong wrote:You are trying to run class DrumKit, but it does not have a main() method. In fact, the main() method is in one of the other classes you wrote. You have to run that other class, not the DrumKit class.

Which is why I suggested that you remove the 'testDrive' class. It's not doing you any good. Just put the main() method in the DrumKit class, as Jesper says. In fact, while you're still in the early stages, my advice would be to stick to general rule of 1 public class per .java file (with the same name as the file too).

Winston

[Craig E. Lewis]

All right I changed my code to this

public class DrumKit {
  public static void main(String[] args) {

    boolean tophat = true;
    boolean snare = true;

    void playTopHat() {
      System.out.println( "ding ding da-ding");
    }
    void playSnare() {
     System.out.println("bang bang ba-bang");
    }
  }
}

but now I have a new problem

C:\Users\Craig\java>java DrumKit
Exception in thread "main" java.lang.NoSuchMethodError: main



[Edit - added code tags - see UseCodeTags for details]

[Matthew Brown]

That code won't compile - you've declared the playTopHat and playSnare methods inside the main method.

[Henry Wong]

Matthew Brown wrote:That code won't compile - you've declared the playTopHat and playSnare methods inside the main method.

And looking at the error message, it looks like the new code changes wasn't compiled -- it is the same error from previous.

Henry

[Craig E. Lewis]

So what would I have to do to get out of main if you don't mind

[Craig E. Lewis]

So what would I have to do if you don't mind ?