Trouble writing a method that takes a string and returns an array of chars

Question

I'm new to Java and stuck on the code below. I don't know how to return the char array; and also if I change the string "purple" to something else, Java won't compile the code.

public class Assigment4 {

    public static void main(String[] args) {
        // I get an error if color is initialized with a longer or shorter string.
        String color = "purple"; 
        char[] a = turnStringtoChar(color);
        System.out.println(a);
    }

    public static char[] turnStringtoChar(String color) {
        char[] letters = {'p', 'u', 'r', 'p', 'l', 'e'};

        for (int i = 0; i < color.length(); i++) {
            // This is the part where I am stuck. I don't know what to return.
            letters[i] = color.charAt(i);
        }

        return letters;
    }

}

Can anyone help me?

What do you want `letters.length` to be (i.e., how many elements do you want in it)? What is `letters.length` the way you've written it? (And I don't believe that the program doesn't compile if you change the string. It probably throws an exception when you run it. This is _not_ the same as saying it won't compile. It is important to learn the difference.) — ajb, Nov 04 '14 at 01:55
Couldn't you just use `toCharArray()`? You could do something like `char[] a = color.toCharArray()` — wns349, Nov 04 '14 at 01:57
i could but i have to create my own method to convert the string into an array of chars — Dee, Nov 04 '14 at 02:00
Look at String's .charAt() method if you can't use toCharArray(). Or is that also not allowed? — MarsAtomic, Nov 04 '14 at 02:04
This question has already been answered [here](http://stackoverflow.com/questions/10006165/converting-string-to-character-array-in-java.) — hfontanez, Nov 04 '14 at 02:11

jcera · Accepted Answer · 2014-11-04T02:21:59.577

2

On your turnStringtoChar method, you need to declare the letters character array in such a way that its length is dependent on the length of the color variable.
So if you have an input that is longer than "purple"; e.g: "yellowwwww";
your program will not throw any errors.

//this is what I am talking about
char[] letters = new char[color.length()];

for (int i = 0; i < color.length(); i++) {
    // this is okay!
    letters[i] = color.charAt(i);
}

Note: I understand this is an assignment and have to implement your own implementation, but for future use, you can use toCharArray() method from String class. usage: color.toCharArray()

edited Nov 04 '14 at 02:21

answered Nov 04 '14 at 02:04

jcera

345
2
11

1

Call me crazy, but the requirement is to create your own method. You could simply do this: `public char[] turnStringtoChar(String color) { return color.toCharArray(); }` After all, you are already using the String API for other purposes. Might as well take full advantage of it. – hfontanez Nov 04 '14 at 02:21

score 0 · Answer 2 · answered Nov 04 '14 at 02:06

0

char[] chars = new char [str.length()];
for (int i=0;i <str.length ();i++) {
    chars [i] = str.charAt (i);
}

answered Nov 04 '14 at 02:06

Steve Siebert

1,874
12
18

Trouble writing a method that takes a string and returns an array of chars

2 Answers2