test code for scala foreach performance test

ScalaFor

object ScalaForApp extends App {
  val scalaFor = new ScalaFor()
  benchmark("testForeach", 10){scalaFor.testForeach()}
  benchmark("testWhile", 10){scalaFor.testWhile()}

  def benchmark(msg: String, times: Int)(f: => Unit): Unit = {
    var i = 0
    val start = System.nanoTime()
    while(i != times){
      f
      i+=1
    }
    println(s"$msg spend: ${(System.nanoTime() - start)/times/1000}")
  }

}
class ScalaFor {

  val total: Int = 1000*1000*1000
  def testForeach(): Unit ={
    var count = 0
    foreach(_ => count += 1)
  }

  def testWhile(): Unit ={
    var i = 0
    while(i != total){
      i+=1
    }
  }

  def foreach(f: Int => Unit): Unit ={
    var i = 0
    while(i != total){
      f(i)
      i+=1
    }
  }
}