Below is the syntax highlighted version of Knuth.java.

/****************************************************************************** * Compilation: javac Knuth.java * Execution: java Knuth < list.txt * Dependencies: StdIn.java StdOut.java * Data files: https://algs4.cs.princeton.edu/11model/cards.txt * https://algs4.cs.princeton.edu/11model/cardsUnicode.txt * * Reads in a list of strings and prints them in random order. * The Knuth (or Fisher-Yates) shuffling algorithm guarantees * to rearrange the elements in uniformly random order, under * the assumption that Math.random() generates independent and * uniformly distributed numbers between 0 and 1. * * % more cards.txt * 2C 3C 4C 5C 6C 7C 8C 9C 10C JC QC KC AC * 2D 3D 4D 5D 6D 7D 8D 9D 10D JD QD KD AD * 2H 3H 4H 5H 6H 7H 8H 9H 10H JH QH KH AH * 2S 3S 4S 5S 6S 7S 8S 9S 10S JS QS KS AS * * % java Knuth < cards.txt * 6H * 9C * 8H * 7C * JS * ... * KH * * % more cardsUnicode.txt * 2♣ 3♣ 4♣ 5♣ 6♣ 7♣ 8♣ 9♣ 10♣ J♣ Q♣ K♣ A♣ * 2♦ 3♦ 4♦ 5♦ 6♦ 7♦ 8♦ 9♦ 10♦ J♦ Q♦ K♦ A♦ * 2♥ 3♥ 4♥ 5♥ 6♥ 7♥ 8♥ 9♥ 10♥ J♥ Q♥ K♥ A♥ * 2♠ 3♠ 4♠ 5♠ 6♠ 7♠ 8♠ 9♠ 10♠ J♠ Q♠ K♠ A♠ * * % java Knuth < cardsUnicode.txt * 2♠ * K♥ * 6♥ * 5♣ * J♣ * ... * A♦ * ******************************************************************************/ package edu.princeton.cs.algs4; /** * The {@code Knuth} class provides a client for reading in a * sequence of strings and <em>shuffling</em> them using the Knuth (or Fisher-Yates) * shuffling algorithm. This algorithm guarantees to rearrange the * elements in uniformly random order, under * the assumption that Math.random() generates independent and * uniformly distributed numbers between 0 and 1. * <p> * For additional documentation, * see <a href="https://algs4.cs.princeton.edu/11model">Section 1.1</a> of * <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne. * See {@link StdRandom} for versions that shuffle arrays and * subarrays of objects, doubles, and ints. * * @author Robert Sedgewick * @author Kevin Wayne */ public class Knuth { // this class should not be instantiated private Knuth() { } /** * Rearranges an array of objects in uniformly random order * (under the assumption that {@code Math.random()} generates independent * and uniformly distributed numbers between 0 and 1). * @param a the array to be shuffled */ public static void shuffle(Object[] a) { int n = a.length; for (int i = 0; i < n; i++) { // choose index uniformly in [0, i] int r = (int) (Math.random() * (i + 1)); Object swap = a[r]; a[r] = a[i]; a[i] = swap; } } /** * Rearranges an array of objects in uniformly random order * (under the assumption that {@code Math.random()} generates independent * and uniformly distributed numbers between 0 and 1). * @param a the array to be shuffled */ public static void shuffleAlternate(Object[] a) { int n = a.length; for (int i = 0; i < n; i++) { // choose index uniformly in [i, n-1] int r = i + (int) (Math.random() * (n - i)); Object swap = a[r]; a[r] = a[i]; a[i] = swap; } } /** * Reads in a sequence of strings from standard input, shuffles * them, and prints out the results. * * @param args the command-line arguments */ public static void main(String[] args) { // read in the data String[] a = StdIn.readAllStrings(); // shuffle the array Knuth.shuffle(a); // print results. for (int i = 0; i < a.length; i++) StdOut.println(a[i]); } } /****************************************************************************** * Copyright 2002-2022, Robert Sedgewick and Kevin Wayne. * * This file is part of algs4.jar, which accompanies the textbook * * Algorithms, 4th edition by Robert Sedgewick and Kevin Wayne, * Addison-Wesley Professional, 2011, ISBN 0-321-57351-X. * http://algs4.cs.princeton.edu * * * algs4.jar is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * algs4.jar is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with algs4.jar. If not, see http://www.gnu.org/licenses. ******************************************************************************/