CODEWITHSUNDEEP
java
suugarpie
suugarpie

Reputation: 31

How to return boolean (primitive) in java?

I'm new to java and as such, I'm not entirely sure if I did this right. What I'm trying to do is find out if the number of items in a list of Strings is even and a primitive.

public class LearnAboutInputs { 
    public boolean isEven(String[] value) {
        if (value.size() % 2 == 0 && boolean == true) {
            return true;
        } else {
            return false;
        }
    }
}

Upvotes: 0

Views: 1686

Answers (3)

Brandon McKenzie
Brandon McKenzie

Reputation: 1685

What you put there is not valid. A minimal edit to make it valid would be:

public class LearnAboutInputs { 
    public boolean isEven(String[] value) {
        if(value.length % 2 == 0) {
            return true;
        }
        else {
            return false;
        }

This assumes you intended to look at the length of the array, as opposed to looking at the size() of a string or strings within.

However, the if check is in itself boolean, so you could more succinctly write:

public class LearnAboutInputs { 
    public boolean isEven(String[] value) {
        return value.length % 2 == 0;
    }

SeeDart and PoisonedYouth bring up a good point about null checking, so adding that to the succinct example results in:

public class LearnAboutInputs { 
    public boolean isEven(String[] value) {
        return value != null && value.length % 2 == 0;
    }

If the value is null, the statement short-circuits to false, so the second half won't be evaluated, making this valid.

If you want to return an object of class Boolean rather than a primitive boolean, change the return type from lowercase ‘boolean’ to the initial-cap ‘Boolean’ word. The handy autoboxing features will do the legwork for you.

public class LearnAboutInputs { 
    public Boolean isEven(String[] value) {  // Return object rather than primitive.
        return value != null && value.length % 2 == 0;  // Autoboxing transforms the generated `boolean` primitive value into a `Boolean` object.
    }

Upvotes: 5

GhostCat
GhostCat

Reputation: 140525

There are various things here. Lets rewrite:

public class LearnAboutInputs { 
  public boolean hasEvenLength(String[] value) {
    if (value != null && value.length % 2 == 0) {
      return true;
    }
    return false;
  }
}

Reasonable changes here:

  • changing the method name to say what the method is doing!
  • avoiding the else-block; simply not required here - and not having the else block makes it even more clear how the possible control flows look like

Upvotes: 0

Skam
Skam

Reputation: 7798

Your code is almost correct. There were a few syntax errors I fixed but I'm not sure what you were trying to do with boolean == true. It's also good practice to make sure your input is valid!

public class LearnAboutInputs { 
    public boolean isEven(String[] value) {
        if (value == null) {
            return false;
        }
        if (value.length % 2 == 0) {
            return true;
        }
        else {
            return false;
        }
    }
}

Upvotes: 3

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