tail recursive function in scala

Inline factorial.scala

def factorial(x: Int) = (2 to x).reduceLeft(_ * _)

Tail recursive factorial.scala

def factorial(i: BigInt): BigInt = {
  def fact(i: BigInt, accum: BigInt): BigInt = i match {
    case _ if i == 1 =>  accum
    case _ => fact(i - 1, i * accum)
  }
  fact(i, 1)
}

// test the function with a for loop implementation

for (i <- 1 to 10) 
  println(format("%s: %s", i, factorial(i)))