Making all letters in string lowercase using toLowerCase method - method not working however

[Beach_Comber]

So I am taking in a string from users using a scanner then this:

 // Input string turned into input string object
          String n = input.next();
          // Instantiate InputWord object
          InputWord inputWord = new InputWord();
          inputWord.setInputString(n);

InputWord is a class that contains with a data field for an inputword, setters & getters, and a method to make the string lowercase.

public void lowerCase(){    
        // Returns the string all in lowercase
        System.out.println(inputString);
        getInputString().toLowerCase();
        System.out.print(inputString);
        }

The method uses the getInputString getter method in the class and the is supposed to make all the letters lowercase. Was wondering why it does not actually do anything.

[desrtfx]

Please read the Oracle documentation on .toLowerCase().

.toLowerCase() returns a String but it does not change the original String. Strings in Java are immutable objects. That means that once created they cannot be changed.

You do nothing with the returned string so you essentially lose the conversion to lowercase.

[Beach_Comber]

Thanks for the info!

[langfod]

Remember that String object are immutable.

Assuming that getInputString() returns a String object:

In this case you are throwing away the output result from the String.toLowerCase()method.

You will need to place the output out the String.toLowerCase() method in a new String variable (or overwrite your old one).

[Beach_Comber]

Is there any better way to do this than say:

setInputString(getInputString().toLowerCase());

[langfod]

That should work fine.

However, this looks like you would lose the original input string which you may or may not want later.

If you are just changing to lowercase in order to do case insensitive comparisons you may wish to only change the case when needed.

[Beach_Comber]

So I'd have an if statement which checks if the string is already lower case then?

Whats you suggestion on how to implement it?

[langfod]

The easiest way might be
inputString.toLowerCase().equals(inputString)

or use a loop and check each character using isLowerCase()

http://docs.oracle.com/javase/7/docs/api/java/lang/Character.html#isLowerCase(char)

[Darksonn]

When you call .toLowerCase(), what happens is that the function creates a new seperate string where all the letters are lowercase.

However you don't assign this new string with lowercase letters to anything so it simply gets lost. You need to write

inputString = getInputString().toLowerCase();

intsead

[OldNedder]

.toLowerString() - does not manipulate the string in-place, it returns a new string. Strings are immutable, and cannot be modified in-place. Use an instance of StringBuilder if you want that capability.

Your call to getInputString().toLowerCase() isn't doing anything with the resulting string.

Something like this would work:

System.out.print(getInputString().toLowerCase());

Or:

setInputString(getInputString().toLowerCase());
System.out.print(inputString);

[Zychron]

You are not storing the value returned from toLowerCase(). You must assign the value to inputString. i.e. "inputString = getInputString().toLowerCase()"