Harry Potter’s World

1) I notice that all names from Harry Potter begin with a capital letter, then have a vowel, and continue with other letters. Write a regular expression that matches such strings.

2) Write a line of code that sets a cooking on the client computer. The cookie should be good for the current session only, and then MAGICALLY disappear.

3) (Yes/No) Can one easily use recursion in Perl?

4) What does the following program do?
(define (wand x)
(if (null? (cdr x))
1
0
)
)

5) Name one difference in how Perl and PHP treat variables.

6) In PHP I have an array named Quidish where the indexes are numbers but not consecutive integers. How can I sum the elements in the array? Write me some code on this MAGICAL paper.

7) In Perl, I need to decide if a file exists. Write me a line of code that can tell if the file exists or not.

8) Name one feature that PHP has that neither Perl, Java, C++ nor Lisp have.



Chose one program from each group.

(1 point) Write me a LISP program that returns the second element of the list.
(2 points) Write me a LISP program that returns the smallest element of the list.

(1 point) Write me a PHP program that Ravenclaw can use for math drills. It should accept two numbers and print their sum.
(2 points) Write me the same program as above, but it should also keep track of how many times the student has used it.

(1 point) Write me a Perl program that decides if ‘Malfoy’ is a user on the system. Malfoy is a user on the system if the file /etc/passwd contains “Malfoy:” as the first 7 characters of any line.
(2 points) Write me a Perl program that prints the longest username on the system. The usernames are stored in the file /etc/passwd as the characters from the beginning of each line to the first “:”.