scala 函数定义方法们

object test extends App{

  val fun1=(x:Int,y:Int)=>x+y
  
  val fun2=((x:Int,y:Int)=>x+y)
  
  val fun3=(_:Int)+(_:Int)
  
  val fun4:(Int,Int)=>Int=(_+_)
  
  val fun5:(Int,Int)=>Int=(x,y)=>x+y
  
  val fun6=new Function2[Int,Int,Int]{
    override def apply(x: Int, y: Int): Int = if(x<y) x else y
  }
  
  val fun7=(x:Int,y:Int)=>if(x<y) x else y
  
  //无参函数,小括号不能省
  val fun8=()=>println("haha")
  fun8()
}