Infinite string creation

Question

I would like to make an 'infinite' list of strings for an application. I attempted to use this....

public static void runinfinite(int length) {
    String lastString= " ";
    while (true) {
        if (lastString.length() > length)
            break;
        lastString = lastString.trim();
        for (char c0 = 'a'; c0 <= 'z'; c0++) {
            lastString += c0;
            action(lastString);
        }
    }
}

It only gives me this: abcdefghijklmnopqrstuvwxyz. Does anyone have a block of code that will make strings 'infinitely'?

Edit: I need it to make a list of strings like this example: [doesn't need to be in the same order, just a bunch of strings]

Edit 2: I want to make this example work better, and run forever.

Answer 1

if you want to make a string of infinite length, you will eventually receive a stackoverflow exception.

likewise:

string badString = "";
Random random = new Random();
while(true)
{
  int asciiNum = random.nextInt(25) + 97;
  badString = badString + Character.toChars(asciiNum);
}

will result in badString consisting of an infinite number of a's, but the program will crash due to a out of memory error.

Please see this for more info:

http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Character.html#toChars%28int%29 http://docs.oracle.com/javase/6/docs/api/java/util/Random.html - random class

Answer 2

if you want to run infinitely, why do you break the loop then?

if (lastString.length() > length)
    break; // <--- it stops your "infinite" loop

what is the meaning of this line?

lastString = lastString.trim();

only thing it does - removes initial space from the very first assignment since you never populate it with whitespace characters. you could as easily use an empty string from the beginning.

it stops after 'z' simply because you probably pass a value less than 26 as your length parameter when calling the function. otherwise it would stop after next 'z' that would make string longer than whatever number you pass in.

upd: you explained it's for max length. then how is it "infinite"? or you want an "infinite" list of strings consisting of characters 'a' through 'z'? or an "infinite" list of the following pattern:

for length = 10:
list = [
"a",
"ab",
"abc",
...
"abcdefghij", // reached max length
"a",
"ab",
...
]

Answer 3

See my comment. It appears you want a stream.

Here's an example...

static final Iterable<Character> alphabet() {
  return new Iterable<Character>() {

    private final char[] ALPHA = new char[] {
        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
        'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
    };

    public final Iterator<Character> iterator() {
      return new Iterator<Character>() {

        private int cursor;

        public boolean hasNext() {
          return true;
        }

        public Character next() {
          char ch = ALPHA[cursor];
          cursor = (cursor + 1) % 26;
          return ch;
        }

        public void remove() {
          throw new UnsupportedOperationException("cannot remove from stream");
        }
      };
    }
  };
}

... coupled with:

for (final char ch : alphabet()) {
  System.out.print(ch);
}