Can you create a Java Iterator over a 2d array?

Can you create a single It开发者_运维技巧erator that will step over all spaces in a 2d array?

If you implement the Iterable interface, you can use a for-each loop. Related examples may be found here.

Yes, wrap the array in an object and make the object implement the iterator interface. So it can be done. I am not aware of any such iterator that ships with the Jdk.

Yes, it can be done, as @Scorpion says. In fact, the solution is probably pretty simple: no more than 10 lines of executable code ... if I correctly understand the problem.

No, there isn't a convenience method in the JDK to do this. And I'm not aware of one in any of the "commons" libraries. (Reason: this particular problem is too specialized to be useful to more than a handful of programmers.)

This should be a sufficient answer for you to go and implement the solution yourself.

Should I / we provide you a potted solution? IMO, no.

• StackOverflow is not a "we write your code for free" service.

• If you do it yourself you will learn more: read the excellent "What have you tried?" blog article.

(And even if someone did feel like writing the code for you, you didn't give a clear enough description of the problem to implement ... without making lots of guesses.)

I dont see the need to make a single iterator when invoking the two from the arrays works just fine as per example:

int 2dArray[][];
for(int 1dArray[]: 2dArray){
    for(int i: 1dArray){
        //do stuff
    }
}

import java.util.LinkedList;
import java.util.Queue;

public class TwoDIterator {
int[][] array;
int outerCursor;
int lastArrayLen;
int totalElems;
int tracker = 1;
Queue<Integer> myQueue = new LinkedList<>();

public TwoDIterator(int[][] arr) {
    this.array = arr;
    this.outerCursor = 0;
    for (int i = 0; i < arr.length; i++) {
        for (int j = 0; j < arr[i].length; j++) {
            totalElems += 1;
        }
    }
    for (int i = 0; i < array[0].length; i++) {
        myQueue.add(array[0][i]);
    }
}

public boolean hasNext() {
    return array.length > outerCursor && totalElems >= tracker;
}

public Integer next() {
    if (myQueue.isEmpty()) {
        outerCursor++;
        for (int i = 0; i < array[outerCursor].length; i++) {
            myQueue.add(array[outerCursor][i]);
        }
        if (!myQueue.isEmpty()) {
            tracker++;
            return myQueue.remove();
        }
    } else {
        tracker++;
        return myQueue.remove();
    }
    return -1;
}

public static void main(String[] args) {
    int[][] arr = { { 1, 2, 3 }, { 1, 3 }, { 1, 2, 5 } };
    TwoDIterator iter = new TwoDIterator(arr);
    while (iter.hasNext()) {
        System.out.println(iter.next());
    }
}
}