harmeetsingh0013

scala> import scala.collection.mutable.ArrayBuffer
import scala.collection.mutable.ArrayBuffer

scala> case class CustomList[A](elements: A*) {
     | 
     |   val elems = new ArrayBuffer[A]
     |   elems ++= elements
     | }
defined class CustomList

harmeetsingh0013

/* Custom Collection */
import scala.collection.mutable.ArrayBuffer

case class CustomList[A](elements: A*) {

  val elems = new ArrayBuffer[A]
  elems ++= elements

  def foreach(c: A => Unit): Unit = {
    elems.foreach(c)

harmeetsingh0013

case class Money(dollars: Int, cents: Int)

trait Data {
  val balance = Money(102, 44)
  val salary = Money(320, 0)
  val balances: Map[String, Money] = Map(
    "James" -> Money(212, 98),
    "Jimmy" -> Money(43, 44)
  )

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  //add money function
  def addMoney(money1: Money, money2: Money): Money = {
    Money(money1.dollars + money2.dollars + ((money1.cents + money2.cents) / 100),
      (money1.cents + money2.cents) % 100)
  }

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// add any two integer value
def addInt(a: Int, b: Int): Int = a + b

// add employe salary to their account balances
def addMoneyMap(balances: Map[String, Money], salary: Map[String, Money]): Map[String, Money] = {
  balances.foldLeft(salaries){
    case (acc, (name, money)) =>
      acc + (name -> acc.get(name).map(addMoney(_ , money)).getOrElse(money))
  }
}

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// generic trait addable
trait Addable[T] {
  def add(a: T, b: T): T
}

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// method abstraction basis on type
def add[A: Addable](a: A, b: A)(implicit addable: Addable[A]): A = addable.add(a, b)

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// add implementation for int type
implicit val addInt = new Addable[Int] {
  override def add(a: Int, b: Int): Int = a + b
}

// add implementation for money type
implicit val addMoney = new Addable[Money] {
  override def add(a: Money, b: Money): Money = {
    Money(a.dollars + b.dollars + ((a.cents + b.cents) / 100),
      (a.cents + b.cents) % 100)

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object Example1Semigroup extends App with Data {

  trait Addable[T] {
    def add(a: T, b: T): T
  }

  implicit val addInt = new Addable[Int] {
    override def add(a: Int, b: Int): Int = a + b
  }

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object Example4Semigroup extends App with Data {

  implicit val moneySemigroup = new Semigroup[Money] {
    override def combine(x: Money, y: Money): Money = {
      Money(x.dollars + y.dollars + ((x.cents + y.cents) / 100),
        (x.cents + y.cents) % 100)
    }
  }

  import cats.instances.int._