//
// simplified program to compute letter grade based on:
//   maximum points (values "hardcoded" in program)
//   and student's points (entered by user)
//

// the next line is needed to avoid warnings with the newest Scala
// "comment it out" (insert a //) if you compile with an earlier version
import scala.io.StdIn._

val MaxExam1 = 100.0
val MaxExam2 = 200.0
val MaxHomework = 200.0

println("enter points for exam1 (max " + MaxExam1 + ")")
val exam1 = readDouble
if (exam1 < 0) {
  println("value must be >= 0")
  sys.exit(0)
}
println("enter points for exam2 (max " + MaxExam2 + ")")
val exam2 = readDouble
if (exam2 < 0) {
  println("value must be >= 0")
  sys.exit(0)
}
println("enter points for homework (max " + MaxHomework + ")")
val homework = readDouble
if (homework < 0) {
  println("value must be >= 0")
  sys.exit(0)
}

val average = (exam1 + exam2 + homework) / (MaxExam1 + MaxExam2 + MaxHomework)
println("average = " + average)

if (average >= .90) {
  println("A- or better")
}
else if (average >= .80) {
  println("B- or better") 
}
else if (average >= .70) {
  println("C- or better")
}
else if (average >= .60) {
  println("D- or better")
}
else {
  println("sorry, F")
}