Is-A vs. Has-A

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# .eight[CSET 160:]
## .eight[Web Development II]

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# OOP: is-a vs has-a

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# Label [Exercise 32](https://github.com/ts-cset/cset-160/blob/master/python/ex32.py)

Find all the:
- classes
- objects
- methods
- attributes

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# Zen Koan

# .eight[What is the difference between a fish and a koi?]

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# Speaking Object-Oriented

- **inheritance**: concept of one class getting traits from another class, like you from your parents
- **composition**: concept of one class being built up from other classes as parts, like a car having wheels
- **is-a**: phrase used to show inheritance, a "koi" **is-a** "fish"
- **has-a**: phrase used to show composition, a "koi" **has-a** "tail"

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# [Exercise 33](https://github.com/ts-cset/cset-160/blob/master/python/ex33.py)

Use the "is-a" and "has-a" phrases to replace each "??" comment in the code.

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# Exercise 33

- What is the difference between .eight[class Name(object)] and .eight[class Name()]? Which should you use?
- Add some functions and variables to the classes that make them do things. How would some of these classes "inherit" these functions and variables?
- What does .eight[super()] do?
  
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# .fourteen[Go through Chapter 43 from the book.]