//
// simplified grade calculations program
// prompt for some grades
// print numeric grade and letter grade
//
val Exam1Max = 100
val Exam2Max = 200
val QuizMax = 10
val NumberOfQuizzes = 6

def getScore(assignment : String, maxPoints : Int) : Int = {
  println("enter your score on " + assignment + " (max " + maxPoints + ")")
  readInt
}

def getQuizScores(quizzes : Array[Int], startIndex : Int) {
  if (startIndex < quizzes.size) {
    quizzes(startIndex) = getScore("quiz " + (startIndex+1), QuizMax)
    getQuizScores(quizzes, startIndex+1)
  }
}

def arraySum(a : Array[Int], startIndex : Int) : Int = {
  if (startIndex < a.size) {
    a(startIndex) + arraySum(a, startIndex + 1)
  }
  else {
    0
  }
}

val exam1 = getScore("exam1", Exam1Max)

val exam2 = getScore("exam2", Exam2Max)

val quizzes = new Array[Int](NumberOfQuizzes)
getQuizScores(quizzes, 0)

val numericGrade = 100 * (exam1 + exam2 + arraySum(quizzes, 0)).toDouble / 
    (Exam1Max + Exam2Max + QuizMax * NumberOfQuizzes)

println("numeric grade is " + numericGrade)

val letterGrade = 
  if (numericGrade >= 90) 'A'
  else if (numericGrade >= 80) 'B'
  else if (numericGrade >= 70) 'C'
  else if (numericGrade >= 60) 'D'
  else 'F';

println("letter grade is " + letterGrade)