CSci 1301: Problem Set 5

Due: Wednesday, Decemeber 5th at 11:59pm

Please make sure that every function has a signature, description, and test cases (as needed).

Problem 1 (10 points)

Exercise 250. Before you write the function, copy tab-sin and tab-sqrt into your Racket file. Then:

1. Write check-expect (or check-within, due to inexact results) tests for tab-sin and tab-sqrt. Don't forget tests for the base cases.
2. Write check expect (or check-within) tests for tabulate to show how it can be used to work as both of the above functions (what functions do you pass to it?)
3. Write the abstract function tabulate and test it.
4. Write its signature (use the format that we used in class or the one the book uses - both are fine).
5. Write one more example of what it can be used for (use check-expects).

Problem 2: Using predefined functions (14 points).

In this task you will be using map and filter general functions given here and foldl, foldr to perform different tasks. You can use helper functions when the functions that you need you need to pass to map or filter aren't defined in Racket. Alternatively you may use lambda if you would like (see section 17.1 in the book).

You may use a combination of function for each problem.

1. Add all of the x coordinates in a list of posn structures.
2. Create a list of 20 squares (images), in which the first one is 1-by-1 pixel, the second one is 2-by-2, and so on (hint: use build-list)
3. Create a list of all even numbers from 0 to 100 (use build-list and possibly other functions, although you can also just do it with build-list)
4. Sort a list of strings by length (shortest first)
5. Sort a list of positions by their distance from (0,0). Note that you need to use sort function and the result must be a list of positions (not of numbers).
6. Count the number of elements in a list (do not write your own recursive function!)
7. Count the number of odd numbers in a list.

CSci 1301 course web site.