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OOP
Basics

Define a class

Declare a class named Greeter that takes a string on creation and greets using this string if you call the "greet" method.
scala
class Greeter(whom : String) { def greet() = { printf("Hello %s\n", whom) } }

(new Greeter("world!")).greet()

Instantiate object with mutable state

Reimplement the Greeter class so that the 'whom' property or data member remains private but is mutable, and is provided with getter and setter methods. Invoke the setter to change the greetee, invoke 'greet', then use the getter in displaying the line, "I have just greeted {whom}.".

For example, if the greetee is changed to 'Tommy' using the setter, the 'greet' method would display:

Hello, Tommy!

The getter would then be used to display the line:

I have just greeted Tommy.
scala
class Greeter(var whom: String) {
def greet() = println("Hello " + whom + "!")
}

// Is this really a private value with getter and setter methods,
// or just a public mutable value?

val greeter = new Greeter("World")
greeter.greet()
greeter.whom = "Tommy"
greeter.greet()
printf("I have just greeted %s.\n", greeter.whom)