Scala example source code file (iq.scala)

This example Scala source code file (iq.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

array, elements, empty, empty, front, head, head, length, queue, queue, string, test, test

The Scala iq.scala source code

/*
 * Test file for immutable queues.
 */

import scala.collection.immutable.Queue

object iq {
  def main {
    /* Create an empty queue. */
    val q: Queue[Int] = Queue.Empty

    /* Test isEmpty. 
     * Expected: Empty 
     */
    if (q.isEmpty) {
      Console.println("Empty")
    }

    /* Test infix enqueing. */
    //val q2 = q + 42 + 0  // deprecated
    val q2 = q.enqueue(42).enqueue(0)

    /* Test is empty and dequeue. 
     * Expected: Head: 42
     */
    val q4 =
      if (q2.isEmpty) {
        Console.println("Empty")
        q2
      } 
      else {
	val (head, q3) = q2.dequeue
        Console.println("Head: " + head)
        q3
      }

    /* Test sequence enqueing. */
    val q5: Queue[Any] = q4.enqueue(List(1,2,3,4,5,6,7,8,9))
    /* Test toString. 
     * Expected: Head: q5: Queue(0,1,2,3,4,5,6,7,8,9) 
     */
    Console.println("q5: " + q5)
    /* Test apply
     * Expected: q5[5]: 5
     */
    Console.println("q5[5]: " + q5(5))

    val q5c: Queue[Int] = Queue.Empty.enqueue(List(0, 1, 2, 3, 4, 5, 6, 7, 8, 9))

    /* Testing ==
     *  Expected: q5 == q9: true
     *            q9 == q5: true
     */
    Console.println("q5 == q5c: " + (q5 == q5c))
    Console.println("q5c == q5: " + (q5c == q5))

    val (_, q6) = q5.dequeue
    val (_, q7) = q6.dequeue
    //val q8 = q7 + 10 + 11  //deprecated
    val q8 = q7.enqueue(10).enqueue(11)
    /* Test dequeu
     * Expected: q8: Queue(2,3,4,5,6,7,8,9,10,11)    
     */
    Console.println("q8: " + q8)
    val q9 = Queue(2,3,4,5,6,7,8,9,10,11)

    /* Testing ==
     *  Expected: q8 == q9: true
     */
    Console.println("q8 == q9: " + (q8 == q9))

    /* Testing elements
     *  Expected: Elements:  1  2  3  4  5  6  7  8  9 
     */
    Console.print("Elements: "); 
    q6.iterator.foreach(e => Console.print(" "+ e + " "))
    Console.println; 

   /* Testing mkString
     *  Expected: String: <1-2-3-4-5-6-7-8-9> 
     */
    Console.println("String: " + q6.mkString("<","-",">"))

    /* Testing length
     *  Expected: Length: 9
     */
    Console.println("Length: " + q6.length)

    /* Testing front
     *  Expected: Front: 1
     */
    Console.println("Front: " + q6.front); 
  }
}

object Test {
  def main(args: Array[String]) {
    iq.main
  }
}