polymorphism.kt

interface Shape {
    fun area(): Double
    fun perimeter(): Double
}
class Square(val side: Double) : Shape {
    override fun area() = side * side
    override fun perimeter() = 4 * side
}
class Circle(val radius: Double) : Shape {
    override fun area() = radius * radius * Math.PI
    override fun perimeter() = 2 * Math.PI * radius
}
class Rectangle(val width: Double, val height: Double) : Shape {
    override fun area() = height * width
    override fun perimeter() = 2 * height + 2 * width
}

fun main() {
    val shapes = listOf(
        Square(5.0),
        Circle(4.0),
        Rectangle(6.0, 7.0)
    )

    val totalArea = shapes.sumByDouble { it.area() }
    println("Total area: $totalArea")

    val totalPerimeter = shapes.sumByDouble { it.perimeter() }
    println("Total perimeter: $totalPerimeter")
}