/*
Marty Stepp, CSE 142, Spring 2010
** This second version breaks the code into methods for better style. **

This program reads a file representing which students attended which
discussion sections and produces output of their scores and grades.

Each line of the file has 45 characters split into nine 5-letter sections.
An 'a' means the student was absent, an 'n' means they attended but
didn't do the section problems, and a 'y' means they did the problems.

The purpose of the program is to demonstrate using an array for tallying,
and to demonstrate text processing with the char data type.


Example input:
yynyyynayayynyyyayanyyyaynayyayyanayyyanyayna
ayyanyyyyayanaayyanayyyananayayaynyayayynynya
yyayaynyyayyanynnyyyayyanayaynannnyyayyayayny


Example output:
Section 1
Student points: [20, 17, 19, 16, 13]
Student grades: [100.0, 85.0, 95.0, 80.0, 65.0]

Section 2
Student points: [17, 20, 16, 16, 10]
Student grades: [85.0, 100.0, 80.0, 80.0, 50.0]

Section 3
Student points: [17, 18, 17, 20, 16]
Student grades: [85.0, 90.0, 85.0, 100.0, 80.0]
*/

import java.io.*;
import java.util.*;

public class Sections2 {
    public static void main(String[] args) throws FileNotFoundException {
        Scanner input = new Scanner(new File("sections.txt"));
        int section = 1;
        while (input.hasNextLine()) {
            // process one section
            String line = input.nextLine();
            int[] points = countPoints(line);
            double[] grades = computeGrades(points);
            results(section, points, grades);
            section++;
        }
    }
    
    // Computes the points earned for each student for a particular section.
    //   Look at the pattern of character indexes to student index.
    //   It wraps around every 5 characters...
    // student 01234012340123401234...
    // index   01234567890123456789...
    // line = "yynyyynayayynyyyayanyyyaynayyayyanayyyanyayna"
    public static int[] countPoints(String line) {
        int[] points = new int[5];
        for (int i = 0; i < line.length(); i++) {
            int index = i % 5;
            int earned = 0;
            if (line.charAt(i) == 'y') {     // c == 'y' or 'n' or 'a'
                earned = 3;
            } else if (line.charAt(i) == 'n') {
                earned = 2;
            }

            // cap the points at 20 for each student
            points[index] = Math.min(20, points[index] + earned);
        }

        return points;
    }
    
    // Computes the percentage for each student for a particular section.
    public static double[] computeGrades(int[] points) {
        double[] grades = new double[5];
        for (int i = 0; i < points.length; i++) {
            grades[i] = 100.0 * points[i] / 20.0;
        }
        return grades;
    }

    // Produces all output about a particular section.
    public static void results(int section, int[] points, double[] grades) {
        System.out.println("Section " + section);
        System.out.println("Student scores: " + Arrays.toString(points));
        System.out.println("Student grades: " + Arrays.toString(grades));
        System.out.println();
    }
}