使用循环Java创建链接列表的链接列表数组

Question

I have successfully implemented Radix sort but I have the following code that I would like to convert to be created by a loop.

private static LinkedList[] bucket = { 
        new LinkedList(), // -9
        new LinkedList(), // -8
        new LinkedList(), // -7
        new LinkedList(), // -6
        new LinkedList(), // -5
        new LinkedList(), // -4
        new LinkedList(), // -3
        new LinkedList(), // -2
        new LinkedList(), // -1
        new LinkedList(), // 0
        new LinkedList(), // 1
        new LinkedList(), // 2
        new LinkedList(), // 3
        new LinkedList(), // 4
        new LinkedList(), // 5
        new LinkedList(), // 6
        new LinkedList(), // 7
        new LinkedList(), // 8
        new LinkedList() // 9
};

However I cannot figure out how I might go about doing this. I tried this but I get compiler errors.

private static LinkedList[] bucket;
int thing = 19;
while(thing != 0){
    bucket = new LinkedList();
    thing--;
}

This is not critical to the functionality of my radix sort as it works flawlessly, I just think it would be cleaner to initialize my buckets with a loop. That said if someone could enlighten me on how to do this I would be very grateful.

Answer 1

Here you go:

private static LinkedList[] bucket = new LinkedList[19];

static {
    for (int i = 0; i < bucket.length; ++i) {
        bucket[i] = new LinkedList();
    }
}

Answer 2

Your LinkedList[] bucket is not initlaized,so you will get NullPointerException at runtime.Also,the syntax of array element assignment is wrong

private static LinkedList[] bucket = new LinkedList[20];
int thing = 19;
while(thing != 0){
    bucket[thing] = new LinkedList();
    thing--;
}

Answer 3

First set up how big the array is going to be (how many LinkedList s are going to be in it), then iterate from zero to that size, and set indices of the array to be new LinkedList s.

For example, if i is your iterator variable, you would say:

bucket[i] = new LinkedList();

Remember what types you're dealing with: a single LinkedList , and an array of them. You can't just assign the entire array to one LinkedList . You have to assign the elements to LinkedList s, to match types.