edu.princeton.cs.algs4.Count Maven / Gradle / Ivy
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/******************************************************************************
* Compilation: javac Count.java
* Execution: java Count alpha < input.txt
* Dependencies: Alphabet.java StdOut.java
* Data files: https://algs4.cs.princeton.edu/50strings/abra.txt
* https://algs4.cs.princeton.edu/50strings/pi.txt
*
* Create an alphabet specified on the command line, read in a
* sequence of characters over that alphabet (ignoring characters
* not in the alphabet), computes the frequency of occurrence of
* each character, and print out the results.
*
* % java Count ABCDR < abra.txt
* A 5
* B 2
* C 1
* D 1
* R 2
*
* % java Count 0123456789 < pi.txt
* 0 99959
* 1 99757
* 2 100026
* 3 100230
* 4 100230
* 5 100359
* 6 99548
* 7 99800
* 8 99985
* 9 100106
*
******************************************************************************/
package edu.princeton.cs.algs4;
/**
* The {@code Count} class provides an {@link Alphabet} client for reading
* in a piece of text and computing the frequency of occurrence of each
* character over a given alphabet.
*
* For additional documentation,
* see Section 5.5 of
* Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.
*
* @author Robert Sedgewick
* @author Kevin Wayne
*/
public class Count {
// Do not instantiate.
private Count() { }
/**
* Reads in text from standard input; calculates the frequency of
* occurrence of each character over the alphabet specified as a
* commmand-line argument; and prints the frequencies to standard
* output.
*
* @param args the command-line arguments
*/
public static void main(String[] args) {
Alphabet alphabet = new Alphabet(args[0]);
final int R = alphabet.radix();
int[] count = new int[R];
while (StdIn.hasNextChar()) {
char c = StdIn.readChar();
if (alphabet.contains(c))
count[alphabet.toIndex(c)]++;
}
for (int c = 0; c < R; c++)
StdOut.println(alphabet.toChar(c) + " " + count[c]);
}
}
/******************************************************************************
* Copyright 2002-2018, 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.
******************************************************************************/