Equals Method problem

[Tiffany Smith]

Hello..... please help ... I'm

I'm trying to compare two integers and return the value to another class, and I keep getting false even though the values are equal:

here is the method:

  public boolean equals(int value2){
		return value == value2;
	}  

if you need the whole probram... here you go...

  /**
 * @(#)workingProject.java
 *
 * workingProject application
 *
 * @author 
 * @version 1.00 2010/1/21
 */
 

  	
public class workingProject {
    
    public static void main(String[] args) {
    	
    	 // Make a new counter
        Counter counter = new Counter();
        System.out.println("Initial value is " + counter.getValue());	
    
    // Test the increment and toString() methods.
        counter.increment();
        counter.increment();
        System.out.println(
            "After two increments, value is " + counter.toString());
            
        // Test the decrement method
        counter.decrement();
        System.out.println("After one decrement, value is " + counter);

		// Test the output() method
        System.out.println("Result of calling counter.output() :");
        counter.output();
        
        // Make a second counter to test equals.
        Counter counter2 = new Counter();
        System.out.println(counter + " equals " + counter2 + "? " +
            counter.equals(counter2));
            
            // Increment counter2 so that they are equal
        counter2.increment();
        System.out.println(counter + " equals " + counter2 + "? " +
            counter.equals(counter2));
            
   		counter.test();//this is a testing method... DELETE ME BEFORE SUBMITTING...................
}
}

class Counter {
    /**
      Current value of the counter
     */
    private int value = 0;
    
//THIS IS WHERE MY CODE STARTS
		
	private int value2;
	private int value2Switch;
		
	public int getValue(){
		return value;
	}
	public void increment(){
		value = value + 1;
		value2Switch = value2Switch + 1;
		if (this.value2Switch >= 2){
			value2 = value2 + 1;
		}
	}
	
	public String toString(){
		return ("" + value);
	}
	public void decrement(){
		if (value >=0)
		{
			value = value - 1;
		}
		else{
		
			System.out.println("The value is no longer valid as it is a negative integer.");
		}
		}
	public void output(){
		System.out.println(value);
	}
	public boolean equals(int value2){
		return value == value2;
	}
		
	public void test()	{
		System.out.println("");
		System.out.println("Testing value variables");
		System.out.println("Value equals " + value);
		System.out.println("Value2 equals " + value2);
		System.out.println("value2Switch equals " + value2Switch);
		System.out.println("");
		
		
	}
		
		
}
	  

Any help you can provide is greatly appreciated... I should have a concussion from beating my head against this wall for so long... *sigh*
Tiffanhy

[Henry Wong]

Hint: Are you sure that you are calling your equals() method? Or the one the you inherited from the Object class?

[Tiffany Smith]

Henry Wong wrote:Hint: Are you sure that you are calling your equals() method? Or the one the you inherited from the Object class?

Thanks for replying Henry. I'm still lost... I'm super noob. I'm in Ch. 4 of a very bad text book with assignments that are less than 1/2 explained. I'm still not sure why it's returning false. I tried comparing the values both within the main method and in my Counter class... but no dice.

What am I doing wrong?

[Jeanne Boyarsky]

Tiffany,
Welcome to JavaRanch!

Take a look at your equals() method. What does it take as a parameter? What are you passing? (it isn't the same type.)

If you don't know the answer to either of these questions, post which one you do know. Or you can see for yourself by renaming your method from "equals" to "equalsValue". This will give you a compiler error rather than functioning in a way to don't expect. And the compiler will answer the questions too.

[Ernest Friedman-Hill]

Jeanne Boyarsky wrote: Or you can see for yourself by renaming your method from "equals" to "equalsValue".

This is a good idea, but note that you have to change the name in two places for this to work. You have to change it where you define the function, and then also change it where you call the function, so i.e.,

... counter.equalsValue(counter2));

[Tiffany Smith]

Jeanne Boyarsky wrote:Tiffany,
Welcome to JavaRanch!

Take a look at your equals() method. What does it take as a parameter? What are you passing? (it isn't the same type.)

If you don't know the answer to either of these questions, post which one you do know. Or you can see for yourself by renaming your method from "equals" to "equalsValue". This will give you a compiler error rather than functioning in a way to don't expect. And the compiler will answer the questions too.

Thanks for the welcome.
I'm actually not passing anything anymore... I deleted the method in the counter class and am just using the following code in the main program:

     // Increment counter2 so that they are equal
        counter2.increment();
        System.out.println(counter + " equals " + counter2 + "? " +
            counter.equals(counter2));   

I think both counter and counter2 are of the Counter class... I'm not getting an incompatible error with the code as it's written right now. Are they string values? I'm totally confused. Sorry to be so totally dense...

Here's my code:

 /**
 * @(#)workingProject.java
 *
 * workingProject application
 *
 * @author 
 * @version 1.00 2010/1/21
 */
 

  	
public class workingProject {
    
    public static void main(String[] args) {
    	
    	 // Make a new counter
        Counter counter = new Counter();
        System.out.println("Initial value is " + counter.getValue());	
    
    // Test the increment and toString() methods.
        counter.increment();
        counter.increment();
        System.out.println(
            "After two increments, value is " + counter.toString());
            
        // Test the decrement method
        counter.decrement();
        System.out.println("After one decrement, value is " + counter);

		// Test the output() method
        System.out.println("Result of calling counter.output() :");
        counter.output();
        
        // Make a second counter to test equals.
        Counter counter2 = new Counter();
        System.out.println(counter + " equals " + counter2 + "? " +
            counter.equals(counter2));
            
            // Increment counter2 so that they are equal
        counter2.increment();
        System.out.println(counter + " equals " + counter2 + "? " +
            counter.equals(counter2));
        
        
                    
   		counter.test();//this is a testing method... DELETE ME BEFORE SUBMITTING HOMEWORK...................
}
}

class Counter {
    /**
      Current value of the counter
     */
    private int value = 0;
    
//THIS IS WHERE MY CODE STARTS
		
	private int value2;
	private int value2Switch;
		
	public int getValue(){
		return value;
	}
	public void increment(){
		value = value + 1;
		value2Switch = value2Switch + 1;
		if (this.value2Switch >= 2){
			value2 = value2 + 1;
		}
	}
	
	public String toString(){
		return ("" + value);
	}
	public void decrement(){
		if (value >=0)
		{
			value = value - 1;
		}
		else{
		
			System.out.println("The value is no longer valid as it is a negative integer.");
		}
		}
	public void output(){
		System.out.println(value);
	}
	/*public boolean equals(int value2){
		return value == value2;
	}*/
		
	public void test()	{ ///TEST MATERIAL FOR DELETION PRIOR TO SUBMISSION
		System.out.println("");
		System.out.println("Testing value variables");
		System.out.println("Value equals " + value);
		System.out.println("Value2 equals " + value2);
		System.out.println("value2Switch equals " + value2Switch);
		System.out.println("");
		

	}
		
		
}
	   

[Tiffany Smith]

Actually... I guess I was wrong about deleting the equals method... my homework assignment specifically calls for one... this just might kill me. Where's my nouse...

please help.... I'm lost and I can't find my way out...

[Henry Wong]

Tiffany Smith wrote:I think both counter and counter2 are of the Counter class... I'm not getting an incompatible error with the code as it's written right now. Are they string values? I'm totally confused. Sorry to be so totally dense...

Just because you are not getting a compiler error doesn't mean that it is correct.

Your equals() method takes an primative int. You are passing it a Counter object. Obviously, these two types are completely incompatible... Something is obviously wrong.

What is wrong is... it is not calling your equals() method, but is calling the equals() method that is inherited from the Object class.... as already mentioned.

Henry

[Tiffany Smith]

Henry Wong wrote:

Tiffany Smith wrote:I think both counter and counter2 are of the Counter class... I'm not getting an incompatible error with the code as it's written right now. Are they string values? I'm totally confused. Sorry to be so totally dense...

Just because you are not getting a compiler error doesn't mean that it is correct.

Your equals() method takes an primative int. You are passing it a Counter object. Obviously, these two types are completely incompatible... Something is obviously wrong.

What is wrong is... it is not calling your equals() method, but is calling the equals() method that is inherited from the Object class.... as already mentioned.

Henry

Okay... that makes sense. Is there a way to make it call my equals method? I guess having two methods with the same name messes things up...

[Rob Spoor]

Does your class have an equals method with exactly the same parameter types as Object.equals? If not then you're not overriding that method but overloading it instead.

Note that an equals method should not throw any exceptions if null is passed, or if the argument is of a completely different class. It should return if that is the case.

[Tiffany Smith]

Rob Prime wrote:Does your class have an equals method with exactly the same parameter types as Object.equals? If not then you're not overriding that method but overloading it instead.

Note that an equals method should not throw any exceptions if null is passed, or if the argument is of a completely different class. It should return if that is the case.

Thanks everyone who replied... I just dropped the class. I am going to try this again with a better textbook/better teacher/and hopefully it will make sense.

[Bert Wilkinson]

From stuck on homework to "dropped the class" in less than 4 hours. Whew, what a trooper!

[Henry Wong]

Bert Wilkinson wrote:From stuck on homework to "dropped the class" in less than 4 hours. Whew, what a trooper!

Well, that is one of the purposes of school. To find what you like. To find what you don't like. To find what you are good at. To find what you are not good at. Better to figure it out now, before you enter the work force.

Henry