CS1321 Fall AY2002
Homework 2
Due Tuesday, August 28, 2001

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 _____ 
|_   _| he following programming problems should be done using DrScheme.
  | |   Be sure to save your function definitions by selecting "Save
  | |   Definitions"/"Save Definitons as" from the "File" menu of DrScheme.
  |_|   You will turn in this assignment during class on Tuesday, August
        28, 2001, so bring a printout of your functions to class.
   (Actually make two printouts: one to keep during class, and one to
   turn in at the beginning of class.)  Since you are handing in the
   program on paper, it does not matter what you call your electronic
   copy of the file.  However, you might as well call it "hw2.scm".
   A similar naming convention will be introduced in future homeworks.

   This assignment must be completed using the design recipe technique
   demonstrated in the text, "How to Design Programs".  In addition to
   the contract outline specified in p. 17, of the text we will add
   and name, gtnumber and class/assignment field.  Thus:

          ;; John Doe
          ;; gt1234a
          ;; cs1321 homework <insert the right HW number>
               
          ;; Contract: area-of-ring: number number --> number
          ;; Purpose : to etc. etc. etc.

 _   _ 
| \ | | ote that this addition appears once at the top of the file, so that
|  \| | we may identify your work.  You do not need to place this at the
| |\  | top of every function.  Please place all of your functions in the
|_| \_| same file.   The major emphasis of this assignment is the design
        recipe technique outlined in the text.  If you are not comfortable 
with this approach, please review the chapter before starting.

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1. Define a function called Celsius->Fahrenheit, a function that takes
   a temperature in Celsius as a paramter and produces the equivalent
   temperature in Fahrenheit.

   You might remember that the formula to convert a Fahrenheit
   temperature to it's Celsius equivalent is C = (5/9) (F - 32).
   Hint: Be sure to solve for F, and not C; look carefully at the
   purpose of the function.

   Useful References:
   "How To Design Programs", p. 10
   Online: http://www.htdp.org/2001-01-18/Book/node18.htm

   The references listed above show you how to combine a similar
   function with a supplied gui and interaction system.  Note,
   however, that the version used in the book works with a
   Fahrenheit->Celsius conversion.


2. For the past few weeks you've been plodding your way through the
   famous Science-Fiction trilogy Red Mars, Green Mars, Blue Mars (by
   Kim Stanley Robinson).  Every measurement concerning the outside
   temperature is measured not in Celsius or Fahrenheit, but in units
   Kelvin.  You think it would be fun to write a function
   Fahrenheit->Kelvin that allows you to take your familiar
   temperature in Fahrenheit and convert it to a temperature in
   Kelvin.

   Write the function, Fahrenheit->Kelvin.  This function takes in a
   single temperature measure in degrees Fahrenheit.

   NOTE:  A measurement in Kelvin is 273 degrees higher than the equivalent
   measurement in Celsius.


3.  Work problem 2.2.4 from "How To Design Programs".

   This problem appears in the "Variables and Programs" section,
   page 11 of the text, and online:

       http://www.htdp.org/2001-01-18/Book/node11.htm

   Hint: The problem suggests you consult a text.  You really should
   not need an algebra text to see how this conversion works.  But if
   you do, consult a TA.