Develop a function convert-reversed that
takes in a list of numbers representing the digits of a decimal number
(ones place first, then tens place, and so on) and returns the
number. This is similar to the convert-3-digits-reversed
function from homework 1, but instead of taking in three digits, it now
takes one argument which is an arbitrary-length list
of digits. For example,
(convert-reversed (list 3 0 5 4 1)) "should be" 14503Note: The reason the digits are in reverse order is that it's actually easier to write the function that way. For extra credit, write a
convert function that does the same
thing, with the digits given in the usual order.
Develop a function plot-points that
takes in a list of posns and draws a little dot on the
screen at each location. The function should return true,
like most of the graphics functions we've seen.
(define-struct employee [name id salary])(Recall that I used this definition to write
total-salary
in class. Review this function and its examples before going on.)
We'll be working with lists of employees; call this the
"employee-list" data type.
With the aid of the templates template-for-employee-list
and template-returning-employee-list,
develop the following functions:
count-over-100K, which takes a list of employees and tells how many of them have a salary over $100,000.give-10%-raises, which takes a list of employees and returns a list of employees with the same names and ID's, but each making 10% more than before.fire-over-100K, which takes a list of employees and returns a new list of employees, leaving out the ones who earned over $100,000.
give-raise, which works on a single
employee. And you'll probably need to use the
"template with values" strategy discussed in class.
Recall the candidate structure you defined in the
previous homework.
We'll be working with lists of candidates; call this the
"candidate-list" data type.
Write several examples of candidate lists.
Write
template-for-candidate-list and
template-returning-candidate-list and comment them out.
Then, with the aid of these templates, develop the following functions:
add-vote-for, which takes in a string (the name of a candidate) and a list ofcandidatestructures, and returns a new list ofcandidatestructures with one more vote recorded for that candidate. Note: the named candidate may not already be in the list at all; handle this case by creating acandidatestructure with that name and one vote. Hint: You may want to write an auxiliary function that works on a single candidate.count-votes, which takes in a list of strings representing votes (e.g.(list "anne" "bob" "anne" "charlie" "charlie" "anne")
and returns a list ofcandidatestructures, each with the correct number of votes. For example, the above list should produce(list (make-candidate "anne" 3) (make-candidate "bob" 1) (make-candidate "charlie" 2))
Note: I don't care about the order of the candidates, only that each one has the right number of votes, so if your function returned
that would be OK.(list (make-candidate "bob" 1) (make-candidate "charlie" 2) (make-candidate "anne" 3) ),winner, which takes in a list ofcandidatestructures and returns the name of the winner. You may assume that the list is non-empty.Hint: You'll need at least one auxiliary function. I see two approaches: one uses an auxiliary function that looks up a given name in a list of candidates, and the other uses an auxiliary function just like
winnerexcept that it returns a wholecandidaterather than just the name. You may use either of these approaches, or any other approach as long as it works.Extra credit: return the string "tie" if there is no single winner.
election, which takes in a list of strings (representing the votes cast by individual voters) and returns a string, the winner of the election. You may assume that there is at least one vote, and that there are no ties for first place. (If you did the extra-credit version of "winner", you can drop the latter assumption.)
Develop a function named
"table-of-squares" which takes in a natural number
n and produces a list of posns, associating each of
the numbers 1...n with its square. For example,
(table-of-squares 5)(list (make-posn 5 25) (make-posn 4 16) (make-posn 3 9) (make-posn 2 4) (make-posn 1 1))Note: I've put these in descending order because it's easier to write the function that way. For extra credit, produce the table in increasing order.
What would happen if you called
plot-points on the result of calling
table-of-squares? Write down what you think will happen,
then try it.
Extra credit: Recall the oranges function
I wrote in class, which takes a natural number and produces an image of the
specified number of oranges, side by side.
Develop a function orange-stack
which takes a natural number and produces an image of a triangular stack
of oranges of the specified height.
Do exercise 11.4.7, a function which tests whether a number is prime.