bijancn

object Cafe {
  //@JavaPeople: We don't need semicolons or the return keyword
  def buyCoffee(creditCard: CreditCard): Coffee = {
    val cup = new Coffee()         // new coffee is created
    creditCard.charge(cup.price)   // side effecting call to outside
    cup                            // cup is returned
  }
}

bijancn

val r1 = (new java.lang.StringBuilder("Hello")).append(" World").toString
// 'Hello World'
val r2 = (new java.lang.StringBuilder("Hello")).append(" World").toString
// 'Hello World'

bijancn

val x = new java.lang.StringBuilder("Hello")
val r1 = x.append(" World").toString
// 'Hello World'
val r2 = x.append(" World").toString
// 'Hello World World'

bijancn

var x = 42
x = x + 1

bijancn

val x = new java.lang.StringBuilder("Hello")
val r1 = x.append(" World").toString
val r2 = x.append(" World").toString

bijancn

val x = "Hello"
val r1 = x + " World"
val r2 = x + " World"

bijancn

def countSpaces(word: List[Char]): Int =
  word.count(_ == ' ')

bijancn

def countSpaces(word: List[Char]): Int =
  word.foldLeft(0)((count: Int, char: Char) =>
    if (char == ' ') {
      count + 1
    } else {
      count
    }
  )

bijancn

trait Foldable[F[_]] {

  def foldLeft[A, B](fa: F[A], b: B)(f: (B, A) => B): B

}

bijancn

def addThree(list: List[Int]): List[Int] = {
  val f = (item: Int) => item + 3
  list.map(f)
}