Welcome to Dr. Racket

Confessions of a Confused Mind

    You will have to use a program called Racket extensively to complete "The Racket Project". 

    The goal of this "lab" is to get you familiar with the environment.  In the spirit of the assignment, the descriptions are VERY sketchy.  (That said, people have succeeded at this project with less help than I am providing here...)  

    Please take this in the spirit in which it is intended. 

Instructions

1. Start the Dr. Racket program.  It may be found on machines in the lab(s) or you may download the Racket version from from the Racket site.
2. Take the Tour through the second chapter. 
3. In the lower window, type (car '(3 4 5)).  See what you get.  Next, try (cdr '(3 4 5)).  Now try (car (cdr '(3 4 5))).  What do car and cdr do?  Can you write an expression that will find the third item in a list?  Does it work if the list has more than three items? 
4. Now, using the model from the the tour, turn your expression into a function named third.  Execute it.
5. Modify third so that it works even if there are fewer than three items in the list.  (Return nil if there is no item.)
6. Finally, write a new function named Nth that takes a list and a number N and returns the Nth item in that list (or nil as appropriate).

Congratulations

    You are well on the way to learning enough Scheme to complete the project.