高阶函数

object base41 {
  def main(args: Array[String]): Unit = {
    val arr =Array(1,2,3,4,5)
    val fn = (x:Int) => x * 2
    val arr1 = arr.map( fn )
    // 用for循环输出
    for(i <- arr1) {
      println(i)
    }
  }
}

object base42 {
  def main(args: Array[String]): Unit = {
    val arr = Array(1, 2, 3, -4)
    val arr1 = arr.map(x=>if(x>0) x else -x)
    for (i <- arr1) {
      println(i)
    }
  }
}