//
// program to take coefficients a, b, c and solve a*x*x + b*x + c = 0
// and print results
//
def roots(a : Double, b : Double, c : Double) {

  println("a = " + a + ", b = " + b + ", c = " + c)

  val d = b*b - 4*a*c

  if (a == 0) {
    if (b == 0) {
      println("not sensible values")
    }
    else {
      val root = -c / b
      println("root is " + root)
    }
  }
  else if (d >= 0) {
    val root1 = (-b + math.sqrt(d)) / (2*a)
      val root2 = (-b - math.sqrt(d)) / (2*a)
      println("roots are " + root1 + ", " + root2)
  }
  else {
    println("no real roots")
  }
}

println("enter coefficients a, b, c (one per line)")
val a = readDouble
val b = readDouble
val c = readDouble
roots(a, b, c)