Class 23 Objectives

At the end of today's class you should

KNOW:

What a state variable is
How to make Racket remember a result that changes over time
Why set! can't be used to change the value of a function argument
That begin can be used to run any number of Racket expressions, but only returns the result of the last expression
When to use begin
That it is OK to define a function which takes no inputs

BE ABLE TO:

Use set! to redefine a named variable
Write programs that change the values of variables
Document variables
Document a function that changes the value of a variable

Sample Exam Question:

Using the data definitions for Account and ListOfAccount and the variable Citibank that we defined in class, write a function remove-account that consumes an account number and removes the account with the given account number from Citibank.

Hint: Use remove-account to call another function, remove-from-list. remove-from-list consumes an account number and a list of accounts and produces a list of accounts with the named account removed.