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105 lines
2.5 KiB
Java
105 lines
2.5 KiB
Java
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import edu.princeton.cs.introcs.StdOut;
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import edu.princeton.cs.introcs.StdRandom;
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/*************************************************************************
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* Compilation: javac Counter.java
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* Execution: java Counter N T
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* Dependencies: StdRandom.java StdOut.java
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*
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* A mutable data type for an integer counter.
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*
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* The test clients create N counters and performs T increment
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* operations on random counters.
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*
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* % java Counter 6 600000
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* 0: 99870
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* 1: 99948
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* 2: 99738
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* 3: 100283
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* 4: 100185
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* 5: 99976
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*
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*************************************************************************/
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/**
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* The Counter class is a mutable data type to encapsulate a counter.
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*
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* For additional documentation, see <a href="/algs4/12oop">Section 1.2</a> of
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* Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.
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*
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* @author Robert Sedgewick
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* @author Kevin Wayne
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*/
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public class Counter implements Comparable<Counter> {
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private final String name; // counter name
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private int count; // current value
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/**
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* Initializes a new counter starting at 0, with the given id.
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* @param id the name of the counter
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*/
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public Counter(String id) {
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name = id;
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}
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/**
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* Increments the counter by 1.
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*/
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public void increment() {
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count++;
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}
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/**
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* Returns the current count.
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*/
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public int tally() {
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return count;
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}
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/**
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* Returns a string representation of this counter
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*/
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@Override
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public String toString() {
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return count + " " + name;
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}
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/**
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* Compares this counter to that counter.
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*/
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public int compareTo(Counter that) {
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if (this.count < that.count) return -1;
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else if (this.count > that.count) return +1;
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else return 0;
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}
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/**
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* Reads two command-line integers N and T; creates N counters;
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* increments T counters at random; and prints results.
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*/
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public static void main(String[] args) {
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int N = Integer.parseInt(args[0]);
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int T = Integer.parseInt(args[1]);
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// create N counters
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Counter[] hits = new Counter[N];
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for (int i = 0; i < N; i++) {
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hits[i] = new Counter("counter" + i);
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}
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// increment T counters at random
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for (int t = 0; t < T; t++) {
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hits[StdRandom.uniform(N)].increment();
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}
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// print results
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for (int i = 0; i < N; i++) {
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StdOut.println(hits[i]);
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}
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}
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}
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