Quick_Sort.java

// this is based upon the tutorial made by geeksforgeeks.org
// https://www.geeksforgeeks.org/quick-sort-algorithm/

import javax.swing.JOptionPane;
public class Quick_Sort {
    public static void main(){
        // get the array size from the user
        int size = 0;
        while(size <= 0){
            size = Integer.parseInt(JOptionPane.showInputDialog("How big is the array you want to sort?"));

            if(size <= 0){
                JOptionPane.showMessageDialog(null, "Array size must be greater than 0");

            }
        }   

        // create a new array and populate each element with the users input
        double[] array = new double[size];
        
        for(int i = 0;i < size; i++){
            array[i] = Double.parseDouble(JOptionPane.showInputDialog("Please enter element " + (i + 1) + " for this array"));
        }

        // output the original array
        System.out.print("\n Original Array: " + array[0]);
        for(int i = 1; i < size; i++){
            System.out.print(", " + array[i]);
        }

        // sort the array
        quickSort(array, 0, array.length - 1);

        // output the sorted array
        System.out.print("\n Sorted Array: " + array[0]);
        for(int i = 1; i < size; i++){
            System.out.print(", " + array[i]);
        }
    }

    private static int count = 0;

    public static void quickSort(double[] array, int low, int high) {
        if (low < high) {
            int pivotIndex = partition(array, low, high);

            count++;
            System.out.print("\n Iteration " + count + ": " + array[0]);
            for(int i = 1; i < array.length; i++){
                System.out.print(", " + array[i]);
            }

            quickSort(array, low, pivotIndex - 1);
            quickSort(array, pivotIndex + 1, high);
        }
    }

    private static int partition(double[] array, int low, int high) {
        double pivot = array[high];
        int i = low - 1;

        for (int j = low; j < high; j++) {
            if (array[j] <= pivot) {
                i++;
                swap(array, i, j);
            }
        }
        swap(array, i + 1, high);
        return i + 1;
    }

    private static void swap(double[] array, int i, int j) {
        double temp = array[i];
        array[i] = array[j];
        array[j] = temp;
    }
}