tp1.scala

// Our generic inteface
trait Shape {
  def area: Double
}

// Implementation 1
class Circle(radius: Double) extends Shape {
  override def area: Double = math.Pi * math.pow(radius, 2)
}

// Implementation 2
class Rectangle(width: Double, length: Double) extends Shape {
  override def area: Double = width * length
}

// Generic function
def areaOf(shape: Shape): Double = shape.area

// Usage
areaOf(new Circle(10))
areaOf(new Rectangle(5, 5))