In addition to the concepts from Quiz 1 and Quiz 2,

You should be able to define the following terms:

• object oriented programming
• class
• instance of a class
• method
• What is meant by the quote: "objects know stuff and can do stuff"?
• graphical user interface or GUI
• pixel
• animation
• formal parameter
• actual parameter (also known as an argument)
• function definition
• function call
• call stack
• scope of a variable

You should understand how to make instances of the following graphics library classes and how to use their methods:

• GraphWin: getMouse()
• Point: getX(), getY()
• Line: getP1(), getP2()
• Circle: getCenter(), getRadius()
• Rectangle: getP1(), getP2()
• Graphical objects can also: draw(window), undraw(), and move(dx, dy)

Practice problems:

1. Write a main program that draws a circle centered in the graphics window with a radius of 100 and draws a line vertically from the top of the graphics window to the bottom. The program should wait for a mouse click to end.
2. Multiple choice problems 1-5, pg. 192
3. Discussion problems 1-5, pg. 193
4. Write a function called avgList that takes a list of numbers as input and returns their average. For example, avgList([5, 10, 5, 4]) should return 6. Write a main program to test the function.
5. Write a function called maxList that takes a list of numbers as input and returns the largest number in the list. For example, maxList([7,4,8,1]) should return 8. Write a main program to test the function.
6. Consider the following program.

   def main():
       print "in main"
       test = "whee"
       check = "e"
       answer = helper(test, check)
       print "the answer is", answer
   
   def helper(word, letter):
       print "in helper"
       print "word:", word
       print "letter:", letter
       x = 0
       for ch in word:
           if ch == letter:
               x = x+1
       # draw stack here
       return x
   
   main()
   

   • Draw the call stack as it would look just prior to returning from helper.
   • What is the program's output (i.e. what is printed when the program is run)?
   • What does the helper funciton compute?
   • What would helper("moobaalalala", "a") return?
   • What would helper("zoo", "a") return?

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