Characters

Exercise 1

Determine the ASCII collating-sequence numbers for the capital letter A and for the lower-case letter a.

Exercise 2

Find out what ASCII character is in position 38 in the collating sequence.

Exercise 3

Do the digit characters precede or follow the capital letters in the ASCII collating sequence?

Exercise 4

If you were designing a character set, where in the collating sequence would you place the space character? Why? What position does it occupy in ASCII?

Exercise 5

In ASCII, the collating-sequence numbers of the control characters are 0 through 31 and 127. Define a predicate char-control? that returns #t if its argument is a control character, #f otherwise.

Exercise 6

Develop a procedure named list-upcase that takes a list of characters as its argument and returns a similar list of characters, but with all of the lower-case letters converted to upper case. Here are a few sample calls to get you started:

> (list-upcase '(#\c #\a #\t))
(#\C #\A #\T)
> (list-upcase '(#\" #\W #\h #\a #\t #\? #\"))
(#\" #\W #\H #\A #\T #\? #\")
> (list-upcase '())
()

Exercise 7

Develop a procedure named remove-whitespace that takes a list of characters as its argument and returns a similar list of characters, excluding all whitespace characters.

> (remove-whitespace '(#\a #\space #\l #\i #\s #\t #\newline))
(#\a #\l #\i #\s #\t)

I am indebted to Professor Ben Gum for his contributions to the development of this lab.