Boolean Array Value Comparison

Question

I have to compare Boolean values in a array by using the isPalindrom() method. I cant not get my program to accurately return the answer if an array is or is not a palindrome. It just always returns true instead of false when I purpose use a non palindrome answer. Code:

 public Boolean isPalindrome()
 {
    Boolean result = true;
    for(int i=0;i<bits.length;i++)
    {
        Boolean a = bits[i];
        Boolean b = bits[bits.length - i - 1];
        if(a!=b)
            result = false;      
    }
    return result;    
 }

For homework, it evidently makes it easier to compare the array as a palindrome. — Lonely Twinky
– Lonely Twinky, Commented Jan 28, 2016 at 3:33
Fairly soon you'll want to learn the difference between the wrapper types (Boolean) and the primitives (boolean). Unless you're putting it into a collection, there's almost never a reason to use the wrapper for boolean. — chrylis -cautiouslyoptimistic-
– chrylis -cautiouslyoptimistic-, Commented Jan 28, 2016 at 3:38

user2173372 · Accepted Answer · 2016-01-28 13:08:09Z

1

Try the code below:

public class TestC {

    public static void main(String[] args) {
        Boolean[] bits = { Boolean.FALSE, Boolean.TRUE, Boolean.FALSE,
                Boolean.FALSE };
        Boolean[] bits1 = { Boolean.TRUE, Boolean.TRUE, Boolean.TRUE,
                Boolean.TRUE };
        Boolean[] bits2 = { Boolean.FALSE, Boolean.TRUE, Boolean.FALSE };
        System.out.println(isPalindrome(bits));
        System.out.println(isPalindrome(bits1));
        System.out.println(isPalindrome(bits2));

    }

    public static Boolean isPalindrome(Boolean[] bits) {
        Boolean result = true;
        for (int i = 0; i < bits.length; i++) {
            Boolean a = bits[i];
            Boolean b = bits[bits.length - i - 1];
            if (a != b)
                result = false;
        }
        return result;
    }
}

answered Jan 28, 2016 at 13:08

user2173372

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1 Comment

Lonely Twinky Over a year ago

Cant use a static method in the Boolean isPalindrome method, I am having to create a constructor, in a separate class, to use in the main class. The static method just throws serval mismatches.

LuvnJesus · Accepted Answer · 2016-01-28 04:19:54Z

1

Perhaps using Integer type (if values are all numeric) would work better than boolean for (a) and (b)?

public Boolean isPalindrome()
     {
        Boolean result = true;
        for(int i=0;i<bits.length;i++)
        {
            int a = bits[i];
            int b = bits[bits.length - i - 1];
            if(a!=b)
                return false;      
        }
        return true;    
     }

edited Jan 28, 2016 at 4:19

answered Jan 28, 2016 at 3:33

LuvnJesus

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6 Comments

Lonely Twinky Over a year ago

Still didn't fix my issue, I know it is just in the lines of codes that I posted. Because when I change the return value to false in the if statement, it interprets the array to not be a palindrome.

LuvnJesus Over a year ago

Rather than store the true/false in a variable, why not simply return false if a mismatch is found and then return true at the end ... I've updated my solution accordingly.

Lonely Twinky Over a year ago

That still did not fix the issue. I have tried all different types of comparison values, even use the compareTo and ect. It just won't return correctly if it is or is not a palindrome.

LuvnJesus Over a year ago

The only item I might try is to remove the boolean type for a and b. I'm not certain what type of values "bits" is comparing, but a standard var type might work better. Otherwise, it would almost certainly return true every time. I've updated my answer again ... we'll get it.

Lonely Twinky Over a year ago

Can't change the boolean to an integer, wont let me do that

|

Nitin Garg · Accepted Answer · 2016-01-28 04:29:18Z

1

instead of != use below code

if (!(a.Equals(b)))

Hope it works.

answered Jan 28, 2016 at 4:29

Nitin Garg

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Comments

Manoj Shrestha · Accepted Answer · 2016-01-28 04:38:37Z

0

The method looks correct, even though it's not the optimized/efficient one. It should return the correct true/false for the palindrome test. Could you provide the set of inputs you're testing with?

answered Jan 28, 2016 at 4:38

Manoj Shrestha

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2 Comments

Lonely Twinky Over a year ago

I am just using one array that I passed the Boolean variables into through the constructor from the main class, its called bits.

Manoj Shrestha Over a year ago

Your code is working for a boolean array e.g. Boolean[] array. Could you show some more code how you're defining and passing the array?

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