ITEC 120 2010fall ibarland

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lect07b
data design with objects

- Reading: §4.1-4.5 (overview of classes, fields, functions("methods"));
      §5.3 (equality and comparison)
- review:
  - exam info
  
  - mutating objects (setting a field) --
    functions which change an object have a return type of                 
  - static fields / named constants; 
  - meaning of 'static', 
  - purpose of constructor

To Teacher:: THIS LECTURE DIDN'T WORK. For starters, move it a bit later, after they've seen a few more classes? (Or maybe I was just off, today.)

For each fo the following, how would we represent them in Java? If you use a class, then include (a) what fields they'd have, and (b) what functions we might have that use them (give signatures). (And some fields we may not be sure how we'd represent — in that case we'll just make up a type like “GeographicRegion” or so.)

Also: should these objects be mutable? (That is, should "same" object change over time ?)

Note: Two notions of equality:

• Song
• Address
• CreditCard
• Pizza (exactly two-toppings)
• race results
• bird species
• a date

---

• Bird (for your aviary)
• Turtle (as used in drawing / turtle graphics from lab)
• product info (for your online store)
• Robot (isTransformed will change. Maybe even isEvil?)
• Goomba example
  Note that they have an 'angry' mode, which eventually stops. How is that implemented?
• Bullet
• Shipment
• the state of an ongoing Volleyball game
• Powerpuff Girl

Note: The name of your class should be a singular noun. So if you are representing race results, you might have class RaceResult: One object (instance) of this class represents one result, so use singular.

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©2010, Ian Barland, Radford University Last modified 2010.Dec.07 (Tue)

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