object CollectionDemo7 {

   def main(args: Array[String]): Unit = {

     //数组使用

     val arr = Array("red", "blue", "yellow")

     arr(0) = "white"

     for(el <- arr){println(el)}

     //用Seq构建List

     println(Seq("red", "blue", "yellow"))

     //用IndexedSeq构建Vector

     println(IndexedSeq("red", "blue", "yellow"))

     //构建Stream lazy集合

     def inc(i: Int): Stream[Int] = Stream.cons(i, inc(i+1))

     val s = inc(1)

     println(s)

     println(s.take(10).toList)

     println(s)

     def addHead(i: Int): Stream[Int] = i #:: addHead(i+1)

     val ss = addHead(1)

     println(ss)

     println(ss.take(10).toList)

     println(ss)

   }

}