Below is the syntax highlighted version of Bubble.java
from §2.1 Elementary Sorts.

/****************************************************************************** * Compilation: javac Bubble.java * Execution: java Bubble N * Dependencies: StdOut.java * * Read strings from standard input and bubblesort them. * ******************************************************************************/ /** * The {@code Bubble} class provides static methods for sorting an * array using bubble sort. * <p> * This implementation makes ~ 1/2 n^2 compares and exchanges in * the worst case, so it is not suitable for sorting large arbitrary arrays. * Bubble sort is seldom useful because it is substantially slower than * insertion sort on most inputs. The one class of inputs where bubble sort * might be faster than insertion sort is arrays for which only * a few passes of bubble sort are needed. This includes sorted arrays, * but it does not include most partially-sorted arrays; for example, * bubble sort takes quadratic time to sort arrays of the form * [n, 1, 2, 3, 4, ..., n-1], whereas insertion sort takes linear time on * such inputs. * <p> * The sorting algorithm is stable and uses O(1) extra memory. * <p> * For additional documentation, * see <a href="https://algs4.cs.princeton.edu/21elementary">Section 2.1</a> of * <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne. * * @author Robert Sedgewick * @author Kevin Wayne */ public class Bubble { // This class should not be instantiated. private Bubble() { } /** * Rearranges the array in ascending order, using the natural order. * @param a the array to be sorted */ public static <Key extends Comparable<Key>> void sort(Key[] a) { int n = a.length; for (int i = 0; i < n; i++) { int exchanges = 0; for (int j = n-1; j > i; j--) { if (less(a[j], a[j-1])) { exch(a, j, j-1); exchanges++; } } if (exchanges == 0) break; } } // is v < w ? private static <Key extends Comparable<Key>> boolean less(Key v, Key w) { return v.compareTo(w) < 0; } // exchange a[i] and a[j] private static <Key extends Comparable<Key>> void exch(Key[] a, int i, int j) { Key swap = a[i]; a[i] = a[j]; a[j] = swap; } // print array to standard output private static void show(Comparable[] a) { for (int i = 0; i < a.length; i++) { StdOut.println(a[i]); } } /** * Reads in a sequence of strings from standard input; bubble sorts them; * and prints them to standard output in ascending order. * * @param args the command-line arguments */ public static void main(String[] args) { String[] a = StdIn.readAllStrings(); Bubble.sort(a); show(a); } }

Last updated: Fri Oct 20 12:50:46 EDT 2017.