Count.java
3.25 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
/******************************************************************************
* Compilation: javac Count.java
* Execution: java Count alpha < input.txt
* Dependencies: Alphabet.java StdOut.java
* Data files: http://algs4.cs.princeton.edu/50strings/abra.txt
* http://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.
* <p>
* For additional documentation,
* see <a href="http://algs4.cs.princeton.edu/55compress">Section 5.5</a> of
* <i>Algorithms, 4th Edition</i> 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 2002-2016, 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.
******************************************************************************/