CMPS 150/151
                   HOMEWORK ASSIGNMENT #7
           Date Assigned:  Wednesday, November 5, 1997
             Due Date: Wednesday, November 19, 1997
                      Due Time: 10:00pm


CMPS 150:
--------

Program file name to be submitted: hmwk7.cc

In addition to the standard initial documentation, your program file
should include the Certification of Authenticity described in hmwk4.

The availability of computers with text manipulation capabilities has 
resulted in some rather interesting approaches to analyzing the writings 
of great authors. Much attention has been focused on whether William
Shakespeare ever lived. Some scholars believe there is substantial 
evidence indicating that Christopher Marlowe actually penned the
masterpieces attributed to Shakespeare. Researchers have used computers to 
find similarities in the writings of these two authors, as well as other
authors. 

Your assignment is to write a program that reads several lines of text and 
outputs the number of occurrences of each letter of the alphabet in the text.
For example, the phrase

	      "To be, or not to be: that is the question:"

contains one 'a', two 'b''s, no 'c''s, ..., six 't''s, etc. (Hint: You may use 
the function tolower(ch) included in <ctype.h> which returns the lowercase 
equivalent of ch, if ch is an uppercase letter, or ch otherwise.)

Additionally, your program should calculate the relative frequency of each 
letter. The relative frequency of a letter is calculated by dividing the number 
of occurrences of this letter in the text by the total number of letters in the 
text. 

You should modularize your program by introducing several functions as follows:
		
    + a function to be used in initializing the variable objects used in your 
      program.

    + a function used to calculate the number of letter occurrences.

    + a function to calculate the relative frequencies.

    + a function to output the results in a readable format.
				 
You should not use global variables.
				      
3.  Compile, and test your program using your own test data. 

4.  Once you are satisfied that your program works, create a hmwk7.test file
    using the command:

    script hmwk7.test

    Run your program against the files 
       Shakespeare:-Hamlet.txt 
       Shakespeare:-King-Lear.txt 
       Shakespeare:-Macbeth.txt 
       Shakespeare:-Othello.txt 
       Shakespeare:-Romeo-and-Juliet.txt
       
    Then run your program against the files 
       Mark-Twain:-A-Tramp-Abroad.txt 
       Mark-Twain:-The-Tragedy-of-Puddnhead-Wilson.txt 
       Mark-Twain:-Tom-Sawyer-Abroad.txt 
       Mark-Twain:-Tom-Sawyer-Detective.txt 

    These files will appear on the class webpage a few days before the due date.  

5.  As a final preparation of the hmwk7.test file, edit it. At the bottom of the 
file, discuss your conclusions regarding your program's potential in author 
attribution. In other words, is it possible to tell the difference between 
works written by two different authors simply based on your program's output?  
Discuss how this program could be improved.

6.  Submit the two files (hmwk7.cc and hmwk7.test) by the due date and time by 
changing to the working directory in which the files reside and issuing the 
appropriate submit command (based on your section).


CMPS 151 only:
-------------

Instead of the above functionality, your program should output a table
indicating the relative frequency of one-letter words, two-letter words, 
three-letter words, etc. appearing in the text. For example, the phrase

     "Whether 'tis nobler in the mind to suffer"

contains zero one-letter words, two two-letter words, two three-letter words, 
two four-letter words (including "'tis"), zero five-letter words, two six-letter 
words, and one seven-letter word. You should consider all word sizes up to ten.  
Any words whose size is greater than ten should still contribute to the calculation 
of relative frequencies of other word sizes.

A word may be delimited by whitespace, or any of the following characters: comma, 
period, exclamation mark, semicolon, and colon. You should modularize your program 
by introducing several functions as follows:
	  
   + a function to be used in initializing the variable objects used in your program.

   + a function to count words; this function should use two help functions:

   + one to skip word delimiters (one or more consecutive word-delimiting 
     characters), and

   + another one to read a word from the input -- actually since you are only 
     interested in knowing what the size of the word is (as opposed to what the 
     actual word is), a good name for this help function is GetSizeOfNextWord).

   + a function to output the results in a readable format.