object FunctionsDay2 {
println("Welcome to the Scala worksheet") //> Welcome to the Scala worksheet
def fact(x:Int) = {
def iter(n:Int, acc:BigInt) : BigInt =
if(n <= 2) acc else iter(n-1, n*acc)
iter(x,1)
} //> fact: (x: Int)BigInt
fact(5) //> res0: BigInt = 60
def sum1(x:Int, y:Int) = {
def iter(n:Int, acc:BigInt) : BigInt =
if(n > y) acc else iter(n+1, n+acc)
iter(x,0)
} //> sum1: (x: Int, y: Int)BigInt
sum1(1,10) //> res1: BigInt = 55
def sumSq(x:Int, y:Int) = {
def iter(n:Int, acc:BigInt) : BigInt =
if(n > y) acc else iter(n+1, n*n+acc)
iter(x,0)
} //> sumSq: (x: Int, y: Int)BigInt
sumSq(1,10) //> res2: BigInt = 385
def sum(f: Int => Int, x:Int, y:Int) = {
def iter(n:Int, acc:BigInt) : BigInt =
if(n > y) acc else iter(n+1, f(n) + acc)
iter(x,0)
} //> sum: (f: Int => Int, x: Int, y: Int)BigInt
def f1(n:Int) = n //> f1: (n: Int)Int
def f2(n:Int) = n * n //> f2: (n: Int)Int
sum(f1,1,10) //> res3: BigInt = 55
sum(f2,1,10) //> res4: BigInt = 385
sum(a => a,1,10) //> res5: BigInt = 55
sum(b => b*b,1,10) //> res6: BigInt = 385
}
