CS 1101 - A-term 11

Homework 6 - Higher-Order Functions; Descendant Trees

Due: Tuesday, October 4 at 5pm

Read the expectations on homework.

Assignment Goals

The Assignment

There are two parts to this assignment. In Part 1, you will use map and filter to re-write some of the list functions we developed a couple of weeks ago. In Part 2, you will define data and functions for a descendant family tree.

Problems

Part 1

In Homework 4 we developed several functions that were designed to process a list of items in an auction. As you solve the following problems, you may refer to and use any of the answers to the HW4 problems. Start by copying and pasting the data definitions and templates for item, bid, and auction from the given solutions to your DrRacket Definitions window.
  1. Using map and/or filter, redefine the function hour-passed, that has the following contract and purpose: 
    ;; hour-passed:  auction -> auction
;; consumes an auction and produces an auction in which the hours left on each biddable item
;; has been decreased by one.  If the number of hours left is zero, the number of hours remain
;; at zero

  2. Using map and/or filter, redefine the function winning-items, that has the following contract and purpose: 
    ;; winning-items:  string auction -> auction (list-of-item)
;; consumes the name of a person and an auction and produces a list of all items for
;; which the named person currently has the highest bid

  3. Using map and/or filter, write a function stuff-won-by-bidder, that has the following contract and purpose: 
    ;; stuff-won-by-bidder:  auction string -> list-of-string
;; consumes an auction and the name of a bidder, and returns a list of the
;; descriptions of the items where the high bidder is the named person, and
;; the time left to bid on the item has expired (is 0)

Part 2

Suppose we're keeping track of people and their children, using a descendant family tree. We're particularly interested in the education levels of the people in the family tree. So, one of the pieces of information we want to keep track of for each person is his or her academic record. A person's academic record consists of a list of yearly records. Each yearly record consists of the grade level, the year the person attended, and whether or not the person passed the grade level in that year. (For example, a person could attend 4th grade in 1991 (didn't pass) and again in 1992 (passed)).For each person, we need to record the person's name, age, academic record, and list of children.
  1. Provide data definitions for the following: yearly-record, academic-record, and person. Provide an example of a descendant family tree that starts with a single person and consists of at least two levels below that person (so there should be information about the person's grandchildren in your example).

  2. Provide the templates for your data definitions.

  3. Develop a function older-than that consumes a person and a number. The function produces a list of the names of each person in the given tree who is older than the given age.

  4. Develop a function increase-age that consumes a person and produces a person. The function adds one to the age of each person in the tree.

  5. Develop a function remove-failures that consumes a person and produces a person. The family tree that is produced is the same as the original, except that each person's academic record now contains only those yearly records that indicate the person passed. You should use filter to produce the updated academic record for each person.

What to Turn In

Here is the grade sheet that the TAs will use when they grade this assignment.

Using web-based turnin, turn in a single file containing all code and documentation for this assignment. Name your file according to the naming conventions for files. Make sure both partners' names and wpi login names appear in a comment at the top of the file.