OoasTools

/*

 Copyright (c) 2003-2006 Niels Kokholm and Peter Sestoft

 Permission is hereby granted, free of charge, to any person obtaining a copy

 of this software and associated documentation files (the "Software"), to deal

 in the Software without restriction, including without limitation the rights

 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 copies of the Software, and to permit persons to whom the Software is

 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in

 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 SOFTWARE.

*/

// C5 example: Find and print the most common words in a text file. 

// Programming pearl by D.E. Knuth in CACM 29 (June 1986) 471-483.

// Compile with 

//   csc /r:C5.dll Commonwords.cs 

using System;                           // Console

using System.IO;                        // StreamReader, TextReader

using System.Text.RegularExpressions;   // Regex

using C5;                               // IDictionary, TreeDictionary, TreeSet

using SCG = System.Collections.Generic; // IComparer

namespace Commonwords {

  class Commonwords {

    static void Main(String[] args) {

      if (args.Length != 2)

        Console.WriteLine("Usage: Commonwords <maxwords> <filename>\n");

      else 

        PrintMostCommon(int.Parse(args[0]), args[1]);

    }

    static void PrintMostCommon(int maxWords, String filename) {

      ICollection<String> wordbag = new HashBag<String>();

      Regex delim = new Regex("[^a-zA-Z0-9]+");

      using (TextReader rd = new StreamReader(filename)) {

        for (String line = rd.ReadLine(); line != null; line = rd.ReadLine()) 

          foreach (String s in delim.Split(line)) 

            if (s != "")

              wordbag.Add(s);

      }

      KeyValuePair<String,int>[] frequency 

        = wordbag.ItemMultiplicities().ToArray();

      // Sorting.IntroSort(frequency, 0, frequency.Length, new FreqOrder());

      Sorting.IntroSort(frequency, 0, frequency.Length, 

          new DelegateComparer<KeyValuePair<String,int>>

                        (delegate(KeyValuePair<String,int> p1, 

                                  KeyValuePair<String,int> p2)

                        { 

                          int major = p2.Value.CompareTo(p1.Value);

                          return major != 0 ? major : p1.Key.CompareTo(p2.Key);

                        }));

      int stop = Math.Min(frequency.Length, maxWords);

      for (int i=0; i<stop; i++) {

        KeyValuePair<String,int> p = frequency[i];

        Console.WriteLine("{0,4} occurrences of {1}", p.Value, p.Key);

      }

    }

    // Lexicographic ordering: decreasing frequency, then increasing string

    class FreqOrder : SCG.IComparer<KeyValuePair<String,int>> { 

      public int Compare(KeyValuePair<String,int> p1, 

                         KeyValuePair<String,int> p2) {

        int major = p2.Value.CompareTo(p1.Value);

        return major != 0 ? major : p1.Key.CompareTo(p2.Key);

      }

    }

  }

}