Computer Science 252
Problem Solving with Java

Fall 2015, The College of Saint Rose

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Agenda

• Announcements
  • Lab 8: Furious Fowl due tonight
• Lecture 14 assignment recap
• Lab 9: Bouncy GUI Ball out
• Recursive structures and methods
• In-class Exercise 15 - (10 lecture assignment points) due before the end of class.

  Augment the NestedSquaresDrag example to include the following additional functionality:

  • All of the FramedRects in the NestedSquares object become red if the mouse moves over the object, and become black again when the mouse is moved off.
  • The NestedSquares object should be hidden when the mouse moves outside the canvas, and shown again when it moves back inside.

  Please demonstrate your program or submit an archive of your project folder by email before you leave class. Email submissions should use a meaningful subject line, clearly indicating the course number and assignment name.

Lecture 15 Assignment

Due at the start of class, Tuesday, October 27.

In preparation for the non-graphical recursive methods we'll be working with, let's refresh your memory of how to write methods that compute and return things. Write a program Methods.java, a Java Application, not a WindowController, with the following functionality:

• A method named area that takes two parameters, a width and a height of a rectangle, and returns its area. (3 points)
• A method named perimeter that takes two parameters, a width and a height of a rectangle, and returns its perimeter. (3 points)
• A method named howManyTwos that takes one parameter, a positive integer, and returns the number of times that number is evenly divisible by 2. Another way to say this is how many times 2 appears in the number's prime factorization. (3 points)
• A main method that tries all three of these out. You should create a keyboard Scanner, prompt your user for input values, and print out what the methods return for those values. (3 points)

Please note that all of your methods will need the static qualifier before their return type to be able to be called easily from main (which must always be a static method).

Terminology

• recursive
• recursive data structure

Examples

• NestedSquaresLoop
• NestedSquaresRec
• NestedSquaresDrag
• BigSnowman

Links

• Don't Worry, Be Happy!