http://www.ntu.edu.sg/home/ehchua/programming/java/j2a_basicsexercises.html

Recommended exercises:
* SumAndAverage
* CheckerBoard
* fibonacci
* Bin2Dec
* GradeStatistics


== Another challenge:
Write a high-low guessing game; have a person think of the number, and have the computer try to guess it. After each guess, the human will tell the computer whether it's higher or lower


== Another challenge: Animal Farm
Create an `abstract class` called `Animal` that has a `mass` and a `name`. These should be `private`.
* All animals should have a constructor which gives them a `mass` and a `name` when they are created
* All animals can `eat` an `amount`, which increases their `mass` by `amount`
* All animals can also `move` a `distance`, which decreases their `mass` by `distance`
* All animals can `speak`, but they all speak differently
* Everybody can use `getName` to get the name of an animal
* Everybody can use `getMass` to get the mass of an animal

Create a class called `Cat` that `extends Animal`
* When a cat `speak`, it prints `Meow!`

Create a class called `Dog` that `extends Animal`
* When a dog `speak`, it prints `Woof!`

Create a class called `Farm`
* The `Farm` has a `main` method
* In the `main` method, the `Farm` creates a `Cat` with a `mass` of `12.2` named `Cloud`
* In the `main` method, the `Farm` creates a `Dog` with a `mass` of `15.4` named `Spot`

In the `main` method, the `Farm` will:
* print the names of both animals and their masses.
  * Ex. `Spot is a Dog with a mass of 15.4.`
* Then, `Cloud` will `eat` `0.2`, `move` `0.8`, and `speak`.
* `Spot` will then `eat` `0.4`,  `move` `0.6`, and `speak`.
* `Farm` will print the names of both animals and their masses once again.

You will probably get weird numbers like 15.200000000001. This is imprecision with floating point numbers, and is normal


== Animal Farm step 2: Constructor Overloading
* All animals can also be created with only a `mass`.
* If an animal is created without a `name`, it's name is set to `Steve` by default.
* All animals now also have a `setName` method which sets their `name`.
* All animals can `printInformation`, which prints information on the specific animal.
  * Ex. `Spot is a Dog with a mass of 15.4`

Create a class called `Hummingbird` 
* All `Hummingbird` have a `wingspan`.
* Hummingbirds must be created with a `mass`, `wingspan`, and `name`.
* When a Hummingbird `speak`, it prints `Tweet!`
* Everybody can use `getWingspan` to get the `wingspan` of a Hummingbird.

`Farm` should:
* Create an array of 5 `Animal` called `animals` that contains:
  * 1 `Dog` with `mass` `10`
  * 1 `Dog` with `mass` `15` and `name` `Fido`
  * 1 `Cat` with `mass` `13` and `name` `Cloud`
  * 1 `Hummingbird` with `mass` `1.1`, `name` `Birdie`, and `wingspan` `2.2`
  * 1 `Cat` with `mass` `5`
* `printInformation` on all `Animal` in the array

Questions to think about:
* `animals[4]` is a `Hummingbird`, but does `animals[4].getWingspan()` work?
* How can you get the wingspan of animals[4]?

== Animal Farm step 3: Method Overloading and Overriding
* All animals can also `eat` other `Animal`, which increases their `mass` by the `mass` of the `Animal` they ate, and sets the `mass` of the `Animal` they ate to `0`.
Hummingbirds are very small, so they will only `eat` a maximum of their own `mass`.
* If a Hummingbird with `mass` `1` eats `5`, it will end with a mass of `2`
* If a Hummingbird with `mass` `2` eats a `Cat` with `mass` `5`, it will end with a mass of `4`, and the `Cat` will end with a `mass` of `0`
* `mass` and `name` should stay `private`. This may be a bit challenging at first, but be creative!
* Hint: `super.method()` will run `method()` of the superclass
From here on out, run whatever code you need in `Farm` to check to make sure your code works the way it is expected to.

== Animal Farm set 4: Enums
* Create an `enum` called `State`, which can be `TAMED`, `PARTIALLY_TAMED`, or `WILD`
* `Cat` and `Dog` all have a `State`. Hummingbirds do not
* It is possible to `getState` of both `Cat` and `Dog`
* `Cat` and `Dog` start with a default `State` of `WILD`
* It is possible to `setState` of `Cat`
* `Dog` can be `tame`, which makes them more tamed (`WILD` -> `PARTIALLY_TAMED`, `PARTIALLY_TAMED` -> `TAMED`, `TAMED` -> `TAMED`)