41

object basic41 {

  def f(n:Int):Int = {
    // 写代码
    if (n == 1) {
      1
    } else {
      f(n - 1) * n
    }
  } : Unit

  def main(args: Array[String]): Unit = {
    val rst = f(4) // 4*3*2*1 = 24
    println(rst)
  }
}
```
```