Gredit.java

import java.util.Scanner;

public class Gredit {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		System.out.print("\nPlease type the student name\t:  ");
		String studentName = input.nextLine();

		// 2D array to store grades for 4 quarters and 5 subjects
		double[][] grades = new double[4][5];

		// 1D array to store averages for later processing		
		double[] quarterAverages = new double[4];

		// Loop through each quarter to get grades and calculate averages
		for (int i = 0; i < 4; i++) {
			quarterAverages[i] = getQuarterAverage(input, studentName, i, grades);
		}

		// Calculate the final average from the quarter averages
		double finalAverage = calculateGrade(quarterAverages);
		System.out.println("\n" + studentName.toUpperCase() + "\'s ACADEMIC YEAR AVERAGE\t:  " + finalAverage + "\n");
		String remarks = (finalAverage <= 74) ? "[You have failed, see you..]" : "[You have passed, congrats!]";

		// Print all grades from the entire academic year
		printGrades(grades, studentName);
		System.out.println("AVE :\t" + finalAverage + "\t" + remarks);
		input.close();
	}

	public static void printGrades(double[][] grades, String studentName) {
		System.out.println("\n" + studentName.toUpperCase() + "\'S GRADES (LYFJSHS ACADEMIC YEAR 2024-2025)");
		
		// Loop through each quarter and print the grades for each subject
		for (int i = 0; i < grades.length; i++) {
			System.out.print("QT" + (i + 1) + " :\t");
			for (int j = 0; j < grades[i].length; j++) {
				System.out.print(grades[i][j] + "\t");
			}
			System.out.println();
		}
	}

	public static double getQuarterAverage(Scanner input, String studentName, int quarterIndex, double[][] grades) {
		// Determine the quarter name based on the index
		String quarter = switch (quarterIndex) {
			case 0 -> "FIRST";
			case 1 -> "SECOND";
			case 2 -> "THIRD";
			case 3 -> "FOURTH";
			default -> "";
		};

		// Get grades for the current quarter and store them in the 2d array
		grades[quarterIndex] = getGrades(input, new String[]{
			"Grade in Applied Science\t:  ",
			"Grade in Oral Communication\t:  ",
			"Grade in Business Mathematics\t:  ",
			"Grade in Information Literacy\t:  ",
			"Grade in Computing Literacy\t:  "
		});

		// Calculate the average for the current quarter
		double average = calculateGrade(grades[quarterIndex]);
		System.out.println("\n" + studentName.toUpperCase() + "\'S " + quarter + " QUARTER AVERAGE\t:  " + average + "\n");
		return average;
	}

	public static double[] getGrades(Scanner input, String[] prompts) {
		// This method handles storing the grades from the user input
		double[] grades = new double[prompts.length];
		for (int i = 0; i < prompts.length; i++) {
			// Calls getValidInput method
			grades[i] = getValidInput(input, prompts[i]);
		}
		return grades;
	}

	public static double getValidInput(Scanner input, String prompt) {
		// This method ensures valid input from the user
		double value = 0;
		while(true) {
			System.out.print(prompt);
			if (input.hasNextDouble()) {
				value = input.nextDouble();
				if (value >= 70 && value <= 100) {
					break;
				} else {
					System.out.println("Please enter a mark within 70 - 100.");
				} 
			} else {
				System.out.println("Invalid input. Please enter a number.");
				input.next();
			}
		}
		return value;
	}

	public static double calculateGrade(double[] numbers) {
		// This method calculates the average of an array of numbers
		double sum = 0;
		for (double number: numbers) {
			sum += number;
		}
		return sum / numbers.length;
	}
}