On the closure function of Scala

object Closure {
  /**scala Closure is a function ： A variable inside a function is not when it acts on , It can still be accessed from outside .
    *  The process of defining a closure function is to capture the free variables outside the function and form a closed function .
    *  When a variable outside a function changes ,scala The closure of can capture the change of variables ,
    * scala Closures capture the variable itself, not its value */

  // Application of closure function , Dependent on variables y, Reference to function closure01 Variables defined outside y
  def closure01(x: Double) = (y: Int) => x*y

  // And closure01 The function is the same ,closure02 The return value of depends on external variables y. Reference to function closure02 Variables defined outside y
  var y = 2
  def closure02(x: Int) = x*y

  def main(args: Array[String]): Unit = {
    val closureValue: Int => Double = closure01(3.5)
    println(closure02(4))
    println(closureValue(3))
  }
}