CS51 - Fall 2009 - Lecture 31

http://www.isi.edu/natural-language/people/knight3.html

counting occurrences of a word in a string
   - public int wordCount(String text, String word){
      int count = 0;
      int index = text.indexOf(word, 0);

      while ( index >= 0 ){
         index = text.indexOf(word, index + 1);
         count++;
      }
    return count;
   }

   - what if we wanted non-overlapping occurrences?
      - index = text.indexOf(word, index + word.length());

characters
   - char: another built-in type (like int, double, ...)
      - char c = 'a';
      - char c = "this is a string".getChar(7);
      - char[] charArray = "this is a string".toCharArray();
   - characters have integer values
      - what can we do with Integer?
         - >, <, >=, <=, ...
         characters have a defined sequence a...z, A...Z, 0...9
   - Character class has some useful static methods (like Integer or Double)
      - http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Character.html
      - Character.isUpperCase(char c)
      - Character.isWhiteSpace(char c);
      - Character.isLetter(char c);
      - Character.isLetterOrDigit(char c);
      - Character.isDigit(char c);

counting the number of sentences
   - For our purposes a sentence is:
      - a string of characters ending in a period followed by a space (or the end of the string)
      - the last word in the sentence should not be capitalized

   - public int sentenceCount(String text){
      String[] words = text.split(" ");
      int count = 0;

      for( String word: words ){
         if( word.endsWith(".") ){
            char first = word.getChar(0);

            if( !(first >= 'A' && first <= 'Z' ){
            // if( Character.isUpperCase(first) )
               count++;
            }
         }
      }
   }

TP2: Pacman
   - read the whole description!
   - extensions
   - design
      - due on 11/25 at 10am
      - won't grade until we grade your final submission