/****************************************************************************** * Compilation: javac Counter.java * Execution: java Counter n trials * Dependencies: StdRandom.java StdOut.java * * A mutable data type for an integer counter. * * The test clients create n counters and performs trials increment * operations on random counters. * * java Counter 6 600000 * 100140 counter0 * 100273 counter1 * 99848 counter2 * 100129 counter3 * 99973 counter4 * 99637 counter5 * ******************************************************************************/ package edu.princeton.cs.algs4; /** * The {@code Counter} class is a mutable data type to encapsulate a counter. *

* For additional documentation, * see Section 1.2 of * Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne. * * @author Robert Sedgewick * @author Kevin Wayne */ public class Counter implements Comparable { private final String name; // counter name private int count = 0; // current value /** * Initializes a new counter starting at 0, with the given id. * * @param id the name of the counter */ public Counter(String id) { name = id; } /** * Increments the counter by 1. */ public void increment() { count++; } /** * Returns the current value of this counter. * * @return the current value of this counter */ public int tally() { return count; } /** * Returns a string representation of this counter. * * @return a string representation of this counter */ public String toString() { return count + " " + name; } /** * Compares this counter to the specified counter. * * @param that the other counter * @return {@code 0} if the value of this counter equals * the value of that counter; a negative integer if * the value of this counter is less than the value of * that counter; and a positive integer if the value * of this counter is greater than the value of that * counter */ @Override public int compareTo(Counter that) { return Integer.compare(this.count, that.count); } /** * Reads two command-line integers n and trials; creates n counters; * increments trials counters at random; and prints results. * * @param args the command-line arguments */ public static void main(String[] args) { int n = Integer.parseInt(args[0]); int trials = Integer.parseInt(args[1]); // create n counters Counter[] hits = new Counter[n]; for (int i = 0; i < n; i++) { hits[i] = new Counter("counter" + i); } // increment trials counters at random for (int t = 0; t < trials; t++) { hits[StdRandom.uniformInt(n)].increment(); } // print results for (int i = 0; i < n; i++) { StdOut.println(hits[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. ******************************************************************************/