Typeclasses2.scala

//simple addition operation, nothing to explain in this v1
def add(a: Int, b: Int): Int = a + b

//Lets make version v1 polymorphic
//below code will fail as the type A may or may not have an + operation
def add[A](a: A, b: A): A = a + b

//so we need a trait which can define that operation for us
trait Num[A] {
    def +(a: A, b: A): A
}

//modified add function in v2
def add[A](a: A, b: A)(implicit n:Num[A]): A = n.+(a, b)

//modified to use type bound this is our version v3
def add[A: Num](a: A, b: A): A = implicitly[Num[A]].+(a, b)

//implimenting the trait
implicit object NumInt extends Num[Int] {
    def +(a: Int, b: Int): Int = a + b
}