Sorting algorithm, Array, smallest number to biggest number?

Question

So I'm a complete beginner and I wanted to try some sorting algorithm which I'm unable to do.

So this is just a blueprint of something that I wanted to begin with:

    package com.company;

    public class Main {
        public static void main(String[] args) {
        // write your code here
            int[] a = {11,7,8,3,15,13,9,19,18,10,4};
            int[] x;
            int merker = a[0]; // the merker has the value 11 now
            int i = 1;
            int n = a.length;

            while(n != 0){
               while(i < n ) {
                   if (a[i] < merker)
                     merker = a[i];
                   i = i + 1;
                }
                merker == x[0];
            }
        }
    }

and than somehow cut out the "merker" for every while loop, till I lay it out like that x[1] = 1 , x[2] = 2

The first while loop would stop when n = 0 which I would have made by cutting out every number that gets sorted in to the other algorithm.

Now it doesn't works at all, and I'm sure I've made tons of mistakes.

At the " merker == x[0]; " position it says, "variable x might not have been initialized.

I hope for help, I'm am extreme noob.

Possible duplicate of [Variable might not have been initialized error](https://stackoverflow.com/questions/2448843/variable-might-not-have-been-initialized-error) — Tom, Sep 29 '19 at 14:44
@Laffa Yett You must initialize int[]x first for example int[]x = new int[size]; and it should work. — , Sep 29 '19 at 14:46
Then don't use an array. Having `x` in your code makes no sense anyway. — Tom, Sep 29 '19 at 15:03
Why dont you try a quicksort algorithm here. Click https://www.geeksforgeeks.org/quick-sort/ to read more. — Mohinuddin Luhar, Sep 29 '19 at 17:52

score 0 · Answer 1 · answered Sep 29 '19 at 15:01

There are multiple things going wrong in your code. Firstly, you haven't initialized array x[]. Secondly, you don't update the value of n so the while loop is sort of an infinite loop.

You can use bubble sort to order the elements as below:

public class Sorting {
    public static void main(String[] args) {
        int[] a = {11,7,8,3,15,13,9,19,18,10,4};
        Arrays.stream(a).forEach(System.out::println);
        int n = a.length;
        for (int i = 0; i < n-1; i++) {
            for (int j = 0; j < n - i - 1; j++) {
                if (a[j] > a[j + 1]) {
                    // swap temp and arr[i]
                    int temp = a[j];
                    a[j] = a[j + 1];
                    a[j + 1] = temp;
                }
            }
        }
    System.out.println("After sorting");
    Arrays.stream(a).forEach(System.out::println);
    }
}

Sorting algorithm, Array, smallest number to biggest number?

1 Answers1