Post-11

• Review all of Modules 12 and 13.

• Complete in-class exercises 11-22 and 25-29 in Module 12, and 1-20 in Module 13. Don't forget to upload these in BB.

• Self-check problems from the book: 3, 9, 11, 14 on pages 178-181.

• In Module 13, we wrote code to take two words (as character arrays) and identify the common prefix. In this exercise, you will take up the more challenging task of identifying the common suffix. Thus, the following

          char[] word = {'n','e','v','e','r'};
          char[] word2 = {'r','i','v','e','r'};
          char[] word3 = {'e','v','e','r'};
          char[] suffix = commonSuffix (word, word2);
          printArray (suffix);
          suffix = commonSuffix (word, word3);
          printArray (suffix);
  

  should print "ver" and "ever". Call your program Suffix.java

• We'll say that a word is an almost-palindrome if the removal of one letter makes the word a palindrome. Thus, the following test code

          char[] word = {'m','a','d','a','m','e'};   // Remove e.
          char[] word2 = {'p','l','o','p',};         // Remove l
          char[] word3 = {'p','r','e','f','e','r'};  // Remove p
          char[] word4 = {'n','e','v','e','r'};      // Won't work.
          checkAlmostPalindrome (word);
          checkAlmostPalindrome (word2);
          checkAlmostPalindrome (word3);
          checkAlmostPalindrome (word4);
  

  should print

    madame is an almost-palindrome: remove e in position 5
    plop is an almost-palindrome: remove l in position 1
    prefer is an almost-palindrome: remove p in position 0
    never is NOT an almost-palindrome
  

  Call your program AlmostPalindrome.java. To get started, you could write a method that takes in an array, and a designated array index, and then returns a new, shorter array with the element at that index removed.

    static char[] shorten (char[] A, int k)
    {
        // Return a new array, of length A.length-1
        // with element k removed.
    }
  

  You already have a method (from class) that checks whether a char-array is a palindrome. Can you use these methods together to solve the almost-palindrome problem?

• In this exercise, we'll have a little fun with characters and music. You don't need any background in music other than to know that we'll use the seven capital letters A, B, C, D, E, F, G to denote musical notes. A tune is a sequence of musical notes. For example: "CCDDCCEECCDDCCEE".

  To hear this tune, download SoundTool.java. Then, in a separate program called MyMusic.java type the following

  public class MyMusic {
  
      public static void main (String[] argv)
      {
  	String music = "CCDDCCEECCDDCCEE";
  	SoundTool.playMusic (music);
      }
  
  }
  

  Your program and SoundTool.java need to be in the same directory. Now compile and execute. Make sure that the sound volume is turned up on your computer. (Note: this will NOT work on hobbes.)

  Now to the exercise. Write a method that produces a randomly generated string using the seven musical notes. The string should be at least 24 letters long. Then, play this string as music with the code in main. So, how to generate such a string randomly? First, find the integer codes that correspond to 'A' through 'G'. Then, all you need to do is generate random integers in this range, and cast to char. To generate a random integer, you can generate a random real number in the desired range, and use the Math.round method to round the real number to an integer. Bring your program to class on Tuesday.

• Don't forget your reflection exercise!

Recommended, but not required:
This week, we'll explore computers and music.

• What exactly is MP3 and how does it work? See this article and video.

• Pandora is an internet radio station that, when you specify your interests, will find songs like the ones you specify. Haven't tried it yet? Give it a try. Then read about how it works.

• Software has been written to compose music. Find such a composition and listen to it. OK, at least the first two minutes.