In addition to the concepts below, you should also know the concepts that were tested on all of the previous quizzes: Quiz 1, Quiz 2, Quiz 3, Quiz 4, Quiz 5.

You should be able to define and explain the following terms:

• Recursion and iteration
• Object-oriented programming, including
  • methods
  • an object's instance variables
  • the constructor, or __init__ method
  • the string, or __str__, method
  • access methods, getters
  • update methods, setters

You should understand and be able to use the following Python concepts:

• Merge sort
• Recursive binary seach
• how variables are stored and function arguments are passed on the stack for recursive functions
• how to create a Python object, including its constructor, string method, and the instance variables that it uses

Practice problems:

1. List the steps merge sort would do to sort the following list: [7, 4, 0, 9, 2, 3, 8, 6, 5,1] (Answer)
2. In the following problem, the recursive function isPalindrome takes a string as an argument, returning True if the string is a palindrome and False otherwise. Draw a stack diagram for the program until the first time at which the program reaches the line marked with a comment below. (Answer)

   def main():
       ans = isPalindrome("badjab")
       print ans
   
   def isPalindrome(s):
       if len(s) <= 1:
           result = True
       elif s[0] != s[len(s)-1]:
           result = False
       else:
           result = isPalindrome(s[1:len(s)-1])
       # draw stack diagram here
       return result
   
   main()
   

3. Write a recursive function reverse() that reverses its input string. (Answer)

      msg = "hello world" print "msg: %s, reversed: %s" % (msg,
      reverse(msg))
   

   Would print:

      msg: hello world, reversed: dlrow olleh
   

4. Write a Student class that stores information for a Swarthmore student. The class should include the following instance variables:
   • id, an integer identifier for the student
   • firstName, a string
   • lastName, a string
   • courses, a list of strings, the course names that the student is enrolled in
   • hobbies, a list of strings, the student's hobbies
   Write the following methods for your Student class:
   • A constructor that, given an id, a first name, and a last name, creates a Student with those values and empty lists of courses and hobbies.
   • A string method that returns a string representing the student.
   • Getter methods for each of the instance variables in the class.
   • An addCourse method that, given a course name, adds that course to the student's course list.
   • An addHobby method that, given a hobby name, adds that hobby to the student's hobby list.
   • A getNumCourses method that returns the number of courses a student is enrolled in.
   • A getNumHobbies method that returns the number of hobbies a student has.
   • A getFreeTime method that returns the value 55 - 12*number-of-courses - 5*number-of-hobbies. (Alternatively, this method could just return 0.)
   (Answer)