/**
 * CS115
 */
import java.util.Scanner;

public class GradeCalculatorProject {

  /* Print specifications – method separate from main */
  public static void main(String[] args) {

    final int MAX_GRADES = 10; // the max arrau length
    final int QUIT = 999; // to quit
    int[] grades = new int[MAX_GRADES]; // array of grades
    int count = 0; // how many grades the user entered
    int total = 0; // calculate the total of grades

    printSpecifications(); // specifications
    Scanner sc = new Scanner(System.in);

    /* Main input loop – stop either on 999 or after 10 grades */
    System.out.print("Enter quiz grade (or 999 to finish): ");
    while (count < MAX_GRADES) {
      int grade = sc.nextInt();

      /* Stop if user typed 999 */
      if (grade == QUIT) {
        System.out.println("...Quitting…");
        break;
      }

      if (grade < 0 || grade > 100) {
        System.out.println("Invalid grade – must be 0‑100.  Try again.");
        continue; // don't count this iteration
      }

      grades[count] = grade; // store the grade
      total += grade; // addition while looping
      count++; // increment number of grades as long as they dont exceed 10.

      System.out.print("Enter next quiz grade (or 999 to finish): ");
    }

    sc.close();

    /* Print all grades entered */
    System.out.println("\n=== All Grades Entered ===");
    for (int i = 0; i < count; i++) {
      System.out.println("Grade #" + (i + 1) + " : " + grades[i]);
      System.out.println("");
    }

    /* Compute average */
    double average = 0.0;
    if (count > 0) {
      average = (double) total / count; // we cast the total since the total is an int
    }
    System.out.printf("\nAverage of %d grades is: %.2f%n", count, average);
    char letterGrade = determineLetterGrade(average);
    System.out.println("Letter grade: " + letterGrade);
    System.out.println("=====  End  =====");
  }

  private static void printSpecifications() {
    System.out.println("\n===== Quiz Grade Calculator =====");
    System.out.println("This program will take 10 quiz grades from 0‑100,");
    System.out.println("Once all the ten inputs are entered, your grades will be printed,");
    System.out.println("and the program will compute your  average score and letter grade.");
    System.out.println("If you wish to QUIT the program please type 999.\n");
    System.out.println("");
  }

  private static char determineLetterGrade(double average) {
    // pretty self exlainatory:qw!
    if (average >= 90)
      return 'A';
    if (average >= 80)
      return 'B';
    if (average >= 70)
      return 'C';
    if (average >= 60)
      return 'D';
    return 'F';
  }
}