/* ---示例代码----*/
scala> val str = 1 #:: 2 #:: Stream.empty
str: scala.collection.immutable.Stream[Int] = Stream(1, ?)
scala> val str = Stream(1,2,4)
str: scala.collection.immutable.Stream[Int] = Stream(1, ?)
scala> def fibFrom(a:Int, b:Int) :Stream[Int] = a #:: fibFrom(b,a+b)
fibFrom: (a: Int, b: Int)Stream[Int]
scala> val fibs = fibFrom(1,1).take(10)
fibs: scala.collection.immutable.Stream[Int] = Stream(1, ?)
scala> fibs.toList
res1: List[Int] = List(1, 1, 2, 3, 5, 8, 13, 21, 34, 55)
/* ---示例代码----*/