 Due date: 10/4 @ 6:00 pm
The goal is to understand data definitions for unions of data
and selfreferential data definitions.
HtDP Problems:
7.2.1, 7.2.2, 9.5.4, 9.5.6, 10.1.7
Additional Problem 1:
A railroad uses three kinds of trains to connect AixaChapelle with
Fobyo:
local , which stops at all four train stations en route;
regional , which stops at Amy and Brian only;
express , which stops only at the destination.
All trains run every day. A train schedule for each kind of train consists
of (1) the time when the train leaves AixaChapelle, (2) when it arrives at
Fobyo, and (3) when it arrives at the intermediate stops, if any.
Your company supplies a software application for assisting the help desk
clerks of this railroad company. Develop a data definition for the train
schedules.
Develop a function that when given a train schedule and a time,
determines whether the train arrives before the given time at its
destination.
Additional Problem 2:
Develop a function that when given a list of Posns,
creates a scene of 100 by 100 and places a solid
yellow disk at each given Posn, if the coordinates
of the Posn are between 0 and 100.
Additional Problem 3:
Develop the function createmovie , which when given a list
of (positive) numbers, creates a list of
that many solid red disks. The radius of the nth solid disk is 10 times
the nth number in the given list.
When you have developed the function, including tests, use the function
runmovie to display the result of your function for some samples:
(bigbang 200 200 0 0)
(runmovie
(createmovie
(cons 10 ...)))
