String into char on 2D array (java)

Question

I am trying to fill a 2D char array with 5 words. Each string must be split into single characters and fill one row of the array.

String str = "hello";
char[][] words = new char[10][5];
words[][] = str.toCharArray();

My error is at the 3rd line I don't know how to split the string "hello" into chars and fill only the 1st row of the 2-dimensional array

do you get an error? If so what's the exact error reported by the compiler? JFC! — Captain Obvlious, Dec 07 '14 at 17:06
@VladfromMoscow I think you mixed up languages, `String` (`java.lang.String`) is valid without any imports, while `std::string` would be c++ — msrd0, Dec 07 '14 at 17:20

msrd0 · Answer 1 · 2014-12-08T19:06:29.967

1

If you want the array to fill the first row, just asign it to the first row:

words[0] = str.toCharArray();

Since this will create a new array in the array, you should change the instantiation of words to this:

char[][] words = new char[5][];

edited Dec 08 '14 at 19:06

answered Dec 07 '14 at 17:08

msrd0

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score -1 · Answer 2 · edited May 23 '17 at 12:31

-1

Java has a String class. Make use of it.

Very little is known of what you want with it. But it also has a List class which I'd recommend as well. For this case, I'd recommend the ArrayList implementation.

Now onto the problem at hand, how would this code look now?

List<String> words = new ArrayList<>();
words.add("hello");
words.add("hello2");
words.add("hello3");
words.add("hello4");
words.add("hello5");

for (String s : words) {
    System.out.println(s);
}

For your case if you are stuck with using arrays.

String str="hello";
char[][] words = new char[5][];
words[][] = str.toCharArray();

Use something along the line of

String str = "hello";
char[][] words = new char[5][];
words[0] = str.toCharArray();

for (int i = 0; i < 5; i++) {
    System.out.println(words[i]);
}

However, why invent the wheel again? There are cases however, more can be read on the subject here.

Array versus List<T>: When to use which?

edited May 23 '17 at 12:31

Community

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answered Dec 07 '14 at 17:33

Emz

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`char[][] words = new char[255][5];` - why `char[255]`? – msrd0 Dec 07 '14 at 19:15
@msrd0 It was just an example. It can be set to the maximum length of the longest word. – Emz Dec 07 '14 at 21:36
Why do you set it at all? This is just unnecesary memory usage, remove it as I posted in my solution – msrd0 Dec 07 '14 at 21:52
@msrd0 will it even compile without? – Emz Dec 07 '14 at 21:53
Of course you can create an two-dimensional array and instantiate the one with containing null values – msrd0 Dec 07 '14 at 21:55
@msrd0 I just tried it in BlueJ, I was not able to do that. – Emz Dec 07 '14 at 21:57
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/66367/discussion-between-emz-and-msrd0). – Emz Dec 07 '14 at 21:59
It does compile without, but notice that you must write `new char[5][]`, not `char[][5]` (sorry, my fault) – msrd0 Dec 08 '14 at 19:07

String into char on 2D array (java)

2 Answers2