CSSE 120 -- Intro. to Software Development

Homework 7

1. Complete the assigned reading for the next session (Zelle sections 6.5-6.7, 7.1-7.3 ).
2. (24 Points) Complete the Angel quiz over this reading. You'll find this on the course Angel page,
   under Lessons → Homework → Homework 7 → More Functions, Decision Structures
3. (10 Points) Finish the exercise you started in class: distance.py, and commit your work using Subclipse.

   A reminder on how to commit:

   1. Make sure you are using the PyDev perspective.
   2. Right click the project or module you would like to commit back to the repository.
   3. Click on Team → Commit
   4. Add an appropriate Commit message then click on the OK button.

4. (40 Points) Function versions of pizza, polygon, and star.  Place all of your function definitions in one Python source file, pizzaPolyStar.py, already in the Session07 project.

   • (10 Points) Create a function called pizza() that has four parameters and draws a pizza slice, similar to Homework 4.  The parameters should be in the following order.
     1. a GraphWin object where it will do its drawing.
     2. a Point, representing the center of the circle.
     3. radius of the circle
     4. number of slices.
   • (10 Points) Create a function called polygon() that has four parameters and draws an inscribed regular polygon, similar to Homework 4. The parameters should be in the following order.
     1. a GraphWin object where it will do its drawing.
     2. a Point, representing the center of the circle.
     3. radius of the circle
     4. number of sides.
   • (20 Points) Create a function called star() that has five parameters and draws an inscribed regular star similar to, but more general than, Homework 4. Note that Star can be called for an even number of points, but only half as many lines as expected will be drawn.  All of our test cases for this one will use an odd number of points. The parameters should be in the following order.
     1. a GraphWin object where it will do its drawing.
     2. a Point, representing the center of the circle.
     3. radius of the circle
     4. number of points of the star (must be odd).
     5. "skip distance".  I.e., the number of polygon vertices that we "move over by" between consecutive vertices of the star.  For example, in the stars in Homework4, the skip distance was 2 (lines were drawn between every other vertex).  A 7-pointed star would have connected vertices 0, 2, 4, 6, 1, 3, 5, 0.  A 7-pointed star with skip distance 3 would connect 0, 3, 6, 2, 5, 1, 4, 0, as pictured below.  Also pictured is a 17-pointed star with skip-distance 5.  A "star" with skip distance 1 is simply a regular polygon.
   • Here is some code that you can use to test your functions (and make sure that they have the correct parameters):

     def main():
         win1 = GraphWin("Window 1", 400, 350)
         win2 = GraphWin("Window 2", 400, 350)
         pizza(win1, Point(50, 50), 40, 10)
         pizza(win1, Point(150, 50), 45, 3)
         star(win1, Point(250, 50), 35, 7, 3)
         polygon(win2, Point(100, 200), 75, 7)
         star(win2, Point(300, 200), 100, 17, 5)
         message = Text(Point(200, 340), "Click this window to end program.")
         message.draw(win1)
         win1.getMouse()
         win1.close()
         win2.close()
     main()
     

   • Here is a sample of output from the above code:
     
   • Bonus: (5 Points) Once you have the star() function working, can you change the body of your polygon() function to just use a single line that invokes your star() function?
   • Commit your Session07  project, with an appropriate comment, to your repository.
5. (40 Points) Create a function called circleOfCircles that takes five parameters and draws N circles whose centers are equally spaced around a (usually) larger circle.  Do not actually draw the circle that they are spaced around.  Parameters:
   1. a GraphWin object where it will do its drawing.
   2. N, the number of circles to draw.
   3. A Point that is the center of the "big" circle that the other circles surround.
   4. The radius of the "big" circle.
   5. The radius of the small circle.

   You should be able to create some interesting patterns by calling your function with various parameters (in a 1000 by 1000 window). You might try (one at a time) the examples are below, along with output from the first one.

   • circleOfCircles(win, 12, Point(200, 200), 100, 15)
   • circleOfCircles(win, 12, Point(500, 500), 300, 40)
   • circleOfCircles(win, 60, Point(500, 500), 300, 50)
   • circleOfCircles(win, 60, Point(500, 500), 50, 300)
   • circleOfCircles(win, 60, Point(500, 500), 150, 300)
   • circleOfCircles(win, 150, Point(500, 500), 150, 300)
   • circleOfCircles(win, 1000, Point(500, 500), 150, 300)
   

   Commit your Session07  project, with an appropriate comment, to your repository.

6. More Python culture: What's up with the shrubbery examples? Check out this visit of King Arthur to the Knights Who Say “Ni!”.