class context parameters.scala

trait Show[T]:
  def show(value: T): String

given Show[Int] with
  def show(value: Int) = s"Int: $value"

given Show[String] with
  def show(value: String) = s"String: $value"

class Printer1[T](value: T)(using ctx: Show[T]):
  println(ctx.show(value))

class Printer2[T: Show](value: T):
  println(summon[Show[T]].show(value))

@main def main = {

Printer1(42)
Printer2("Scala 3")

}