• 編寫函式values(fun:(Int)=>Int,low:Int,high:Int),該函式輸出一個集合，對應給定區間內給定函式的輸入和輸出。比如，values(x=>x*x,-5,5)應該產出一個對偶的集合(-5,25),(-4,16),(-3,9),…,(5,25)

def values( fun:(Int) => Int, low :Int, high:Int)={
    var arr = List[(Int,Int)]()
    low to high foreach{
        num => arr = (num,fun(num)) :: arr
    }
    arr
}
values(x => x*x, -5
 
,5).foreach(print(_))
//輸出結果為：(5,25)(4,16)(3,9)(2,4)(1,1)(0,0)(-1,1)(-2,4)(-3,9)(-4,16)(-5,25)

• 如何用reduceLeft得到陣列中的最大元素?

val a=Array(1.1,2.1,3.1,0.1,4.1) 
a.reduceLeft((a,b) => if(a>b) a else b)

• 用to和reduceLeft實現階乘函式,不得使用迴圈或遞迴

println(1 to 3 reduceLeft(_ * _))