Decimal to roman numeral converter in scala

Scala program for Decimal to roman numeral converter. Here mentioned other language solution.

//  Scala program for
//  Conversion from Decimal to roman number
class Perform ()
{
    // Display roman value of n
    def show(n : Int) : Unit=
    {
        if (n==1)
        {
            print("I")
        }
      	else if(n==4)
        {
            print("IV")
        }
        else if(n==5)
        {
            print("V")
        }
        else if(n==9)
        {
            print("IX")
        }
        else if(n==10)
        {
            print("X")
        }
        else if(n==40)
        {
            print("XL")
        }
        else if(n==50)
        {
            print("L")
        }
        else if(n==90)
        {
            print("XC")
        }
        else if(n==100)
        {
            print("C")
        }
        else if(n==400)
        {
            print("CD")
        }
        else if(n==500)
        {
            print("D")
        }
        else if(n==900)
        {
            print("DM")
        }
        else if(n==1000)
        {
            print("M")
        }
    }
    def select(number : Long, 
               collection : Array[Int], size : Int) : Long=
    {
        var n = 1
        var i = 0
        while (i < size)
        {
            if (number >= collection(i))
            {
                n = collection(i)
            }
            else
            {
                i = size;
            }
            i += 1
        }
        show(n)
        // Reduce the value of number
        return number - n
    }
    def roman(num : Long) : Unit=
    {
      	var number = num;
        if (number <= 0)
        {
            // When is not a natural number
            return
        }
        // Base case collection
        var collection =
        Array(1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000)
        // Get the size of collection
        var size = collection.length
        print(" " + number + " : ")
        while (number > 0)
        {
            number = select(number, collection, size)
        }
        println()
    }
}

object Main 
{
	def main(args : Array[String]) : Unit=
    {
        var task = new Perform()
        // Test Case
        task.roman(10)
        task.roman(18)
        task.roman(189)
        task.roman(604)
        task.roman(982)
        task.roman(3000)
    }
}

Output

 10 : X
 18 : XVIII
 189 : CLXXXIX
 604 : DCIV
 982 : DMLXXXII
 3000 : MMM