Scala By Example: Case 类与模式匹配 习题

   1: abstract class IntTree

   2: case object EmptyTree extends IntTree

   3: case class Node(elem: Int, left: IntTree, right: IntTree) extends IntTree

   4:  

   5: def contains(t: IntTree, v: Int): Boolean = t match {

   6:     case EmptyTree => false

   7:     case Node(e, l, r) => e == v || contains(l, v) || contains(r, v)

   8: }

   9:  

  10: def insert(t: IntTree, v: Int): IntTree = t match {

  11:     case EmptyTree => Node(v, EmptyTree, EmptyTree)

  12:     case Node(e, l, r) =>

  13:         if(e == v) t

  14:         else if(e > v) Node(e, insert(l, v), r)

  15:         else Node(e, l, insert(r, v))

  16: }

目前为止最简单的习题了，不解释。好的编程语言就像说话一样自然！

Technorati 标签: Scala