def f(n: Int) = print("Hello World\n" * n)
2
non-functional 1
def f(n: Int) = { for (i <- 1 to n) println("Hello World") }
3
non-functional 2
def f(n: Int) = { for(i <- Iterator.range(0,n)) println("Hello World"); }
4
recursive
def f(n:Int):Unit = if(n>0) { println("Hello World") f(n-1) }