CodeToLive

Scala Classes & Objects

Learn object-oriented programming in Scala.

Class Definition

class Person(val name: String, var age: Int) {
  // Class body
  def greet(): String = s"Hello, my name is $name"
  
  // Method with default parameter
  def incrementAge(years: Int = 1): Unit = {
    age += years
  }
}

Object Instantiation

val alice = new Person("Alice", 25)
println(alice.greet())  // Hello, my name is Alice
alice.incrementAge()
println(alice.age)      // 26

Companion Objects

class Circle(val radius: Double)

object Circle {
  // Factory method
  def apply(radius: Double): Circle = new Circle(radius)
  
  def area(circle: Circle): Double = 
    math.Pi * circle.radius * circle.radius
}

val circle = Circle(5.0)  // Using apply method
println(Circle.area(circle))

Case Classes

case class Point(x: Int, y: Int) {
  def +(other: Point): Point = 
    Point(x + other.x, y + other.y)
}

val p1 = Point(1, 2)
val p2 = Point(3, 4)
val p3 = p1 + p2  // Point(4, 6)

Inheritance

abstract class Shape {
  def area: Double
}

class Rectangle(width: Double, height: Double) extends Shape {
  override def area: Double = width * height
}

class Circle(radius: Double) extends Shape {
  override def area: Double = math.Pi * radius * radius
}

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