Lösung

object BMI2 extends App {

def isNumber(s: String): Boolean = {
    try {
      s.toDouble
      return true
    } catch {
      case e: Exception => return false
    }
 }

var kg = readLine("Please enter your body mass in kg ")
var m = readLine("Please enter your body height in m ")


if (isNumber(kg)==true && isNumber(m)==true)
{
        var kg1 =kg.toDouble
        var m1 = m.toDouble

        if (kg1>=0 && m1>=0)
        {
        var bmi = kg1/(math.pow(m1,2))

        if (bmi <18.5)
        {
            print("You are under the ideal weight!")
        }
        else if (bmi <24.9)
        {
            print("You do have normal weight :-)")
        }
        else if (bmi <29.9)
        {
            print("You are above the ideal weight!")
        }
        else if (bmi >30)
        {
            print("Your weight is considerably above the ideal weight!")
        }

        } else {
            print("Negative values are not valid!")
        }
}else{
    print("Please only enter numeric values!")
}

}