Question

Program: Please read the complete prompt before going into coding. Write a program that handles the gradebook for the instructor. You must use a 2D array when storing the gradebook. The student ID as well as all grades should be of type int. To make the test process easy, generate the grade with random numbers. For this purpose, create a method that asks the user to enter how many students there are in the classroom. Then, in each iteration it asks the user to enter the student number and will generate 3 random Lab Test scores between 55-95, 4 Lecture Tests between 60-90, 5 assignments between 58-100 per student. To get the highest grade, you need to create as many methods as you feel is needed. Each method has to have a brief comment on top explaining why you have created this method and what is it doing. In the end you should have a gradebook that looks something like this. Notice how all of the data itself is stored as a 2D array. The headers that say ID#, Lab 1, Lab2, etc do not need to be stored in the array. You will need to print this header out before displaying the gradebook. ID# Lab1 Lab2 Lab3 Lec1 Lec2 Lec3 Lec4 HW1 HW2 HW3 HW4 HW5 Avg 801395 84 65 71 88 72 8392 98 69 97 82 952571 78 73 74 B2 B9 78 80 89 74 66 79 77 623956 68 64 85 81 79 80 70 92 97 62 91 77 You need to provide a menu to the user to do the following with the array: Note: Users should be able to enter numbers for the options. Main Menu: 1. Display the highest score of all grades. 2. Display the lowest score of all grades. 3. Display the entire gradebook. 4. Go to Individual Student Menu 5. Export gradebook as a text file (Extra Credit). 6. Quit

using java

Answer 1

/*
* Class to store grade book
*/
import java.io.FileWriter;
import java.util.Random;
import java.util.Scanner;

public class GradeBook {

    // variables
    int gradeBook[][];
    int scores = 12;
    Scanner in = new Scanner(System.in);

    // main method
    public static void main(String[] args) {
        GradeBook g = new GradeBook();
        g.getGrades();
        g.executeMenu();
    }

    // method to get grades
    private void getGrades() {
        System.out.print("How many students in the class? ");
        int n = getInt();
        gradeBook = new int[n][scores + 1];
        // object to create random number
        Random rand = new Random();
        for (int i = 0; i < n; i++) {
            System.out.print("Enter studnet number: ");
            int num = getInt();
            gradeBook[i][0] = num;
            for (int j = 1; j < 4; j++) {
                // create random number between 55 and 95
                num = rand.nextInt((95 - 55) + 1) + 55;
                gradeBook[i][j] = num;
            }
            for (int j = 4; j < 8; j++) {
                // create random number between 60 and 90
                num = rand.nextInt((90 - 60) + 1) + 60;
                gradeBook[i][j] = num;
            }
            for (int j = 8; j < 13; j++) {
                // create random number between 58 and 100
                num = rand.nextInt((100 - 58) + 1) + 58;
                gradeBook[i][j] = num;
            }
        }
    }

    // method to get integer input
    private int getInt() {
        try {
            int n = Integer.parseInt(in.nextLine());
            return n;
        } catch (NumberFormatException e) {
            System.out.println("Invalid entry.. integer expected");
            return getInt();
        }
    }

    // method to execute main menu
    private void executeMenu() {
        // loop
        while (true) {
            System.out.println("1. Display highest score of all grades");
            System.out.println("2. Display lowest score of all grades");
            System.out.println("3. Display entire grade book");
            System.out.println("4. Go to individual student menu");
            System.out.println("5. Export grade book as txt file");
            System.out.println("6. Quit");
            System.out.print("Enter your option: ");
            int option = getInt();
            switch (option) {
                case 1:
                    displayHighest();
                    break;
                case 2:
                    displayLowest();
                    break;
                case 3:
                    displayGrades();
                    break;
                case 4:
                    gotoStudentMenu();
                    break;
                case 5:
                    exportGrade();
                    break;
                case 6:
                    break;
                default:
                    System.out.println("Invalid entry");
                    break;
            }
            // exit loop condition
            if (option == 6) {
                break;
            }
        }
    }

    // method to dispaly highest
    private void displayHighest() {
        int highest = gradeBook[0][1];
        for (int i = 0; i < gradeBook.length; i++) {
            for (int j = 1; j < gradeBook[i].length; j++) {
                if (highest < gradeBook[i][j]) {
                    highest = gradeBook[i][j];
                }
            }
        }
        System.out.println("Highest grade: " + highest);
    }

    // method to display lowest
    private void displayLowest() {
        int lowest = gradeBook[0][1];
        for (int i = 0; i < gradeBook.length; i++) {
            for (int j = 1; j < gradeBook[i].length; j++) {
                if (lowest > gradeBook[i][j]) {
                    lowest = gradeBook[i][j];
                }
            }
        }
        System.out.println("Lowest grade: " + lowest);
    }
  
    // method to dispaly all grades and average
    private void displayGrades() {
        System.out.println("ID#\tLab1\tLab2\tLab3\tLec1\tLec2\tLec3\tLec4\t"
                + "HW1\tHW2\tHW3\tHW4\tHW5\tAvg");
        for (int i = 0; i < gradeBook.length; i++) {
            int total = 0;
            System.out.print(gradeBook[i][0] + "\t");
            for (int j = 1; j < gradeBook[i].length; j++) {
                System.out.print(gradeBook[i][j] + "\t");
                total += gradeBook[i][j];
            }
            System.out.println(total / scores);
        }
    }

    // student menu
    private void gotoStudentMenu() {
        System.out.print("Enter student ID: ");
        int id = getInt();
        int row = -1;
        for (int i = 0; i < gradeBook.length; i++) {
            if (gradeBook[i][0] == id) {
                row = i;
                break;
            }
        }
        // if no students with given id, return from method
        if (row == -1) {
            System.out.println("Student not found..");
            return;
        }
        // loop
        while (true) {
            System.out.println("7. Display all the lab grades and average lab score");
            System.out.println("8. Display all the lecture grades and average lecture score");
            System.out.println("9. Display all the assignment grades and average assignment score");
            System.out.println("10. Display the letter grade");
            System.out.println("11. Back to main menu");
            System.out.print("Enter your option: ");
            int option = getInt();
            switch (option) {
                case 7:
                    displayLabGrades(row);
                    break;
                case 8:
                    displayLecGrades(row);
                    break;
                case 9:
                    displayAssignmentGrades(row);
                    break;
                case 10:
                    displayLetterGrade(row);
                    break;
                case 11:
                    break;
                default:
                    System.out.println("Invalid entry");
                    break;
            }
            // exit loop condition
            if (option == 11) {
                break;
            }
        }
    }

    // method to display lab grades and average
    private void displayLabGrades(int row) {
        System.out.println("ID#\tLab1\tLab2\tLab3\tAvg");
        int total = 0;
        System.out.print(gradeBook[row][0] + "\t");
        for (int j = 1; j < 4; j++) {
            System.out.print(gradeBook[row][j] + "\t");
            total += gradeBook[row][j];
        }
        System.out.println(total / 3);

    }

    // method to display Lecture grades and average
    private void displayLecGrades(int row) {
        System.out.println("ID#\tLec1\tLec2\tLec3\tLec4\tAvg");
        int total = 0;
        System.out.print(gradeBook[row][0] + "\t");
        for (int j = 4; j < 8; j++) {
            System.out.print(gradeBook[row][j] + "\t");
            total += gradeBook[row][j];
        }
        System.out.println(total / 4);

    }

    // method to display assignemt grades and average
    private void displayAssignmentGrades(int row) {
        System.out.println("ID\tHW1\tHW2\tHW3\tHW4\tHW5\tAvg");
        int total = 0;
        System.out.print(gradeBook[row][0] + "\t");
        for (int j = 8; j < 13; j++) {
            System.out.print(gradeBook[row][j] + "\t");
            total += gradeBook[row][j];
        }
        System.out.println(total / 5);
    }

    // method to display letter grade
    private void displayLetterGrade(int row) {
        int total = 0;
        for (int j = 1; j < 13; j++) {
            total += gradeBook[row][j];
        }
        int average = total / scores;
        char grade;
        if (average > 79) {
            grade = 'A';
        } else if (average > 69) {
            grade = 'B';
        } else if (average > 59) {
            grade = 'C';
        } else if (average > 49) {
            grade = 'D';
        } else {
            grade = 'F';
        }
        System.out.println("Letter grade: " + grade);
    }

    // method to export all grades to txt file
    private void exportGrade() {
        try {
            FileWriter fw = new FileWriter("gradebook.txt");
            fw.write("ID#\tLab1\tLab2\tLab3\tLec1\tLec2\tLec3\tLec4\t"
                    + "HW1\tHW2\tHW3\tHW4\tHW5\tAvg\n");
            for (int i = 0; i < gradeBook.length; i++) {
                int total = 0;
                fw.write(gradeBook[i][0] + "\t");
                for (int j = 1; j < gradeBook[i].length; j++) {
                    fw.write(gradeBook[i][j] + "\t");
                    total += gradeBook[i][j];
                }
                fw.write(total / scores + "\n");
            }
            fw.close();
        } catch (Exception e) {
            System.out.println(e);
        }
        System.out.println("Success...");
    }
}

Output

How many students in the class? 5 Enter studnet number: 1234 Enter studnet number: 1235 Enter studnet number: 1236 Enter studnet number: 1237 Enter studnet number: 1238 1. Display highest score of all grades 2. Display lowest score of all grades 3. Display entire grade book 4. Go to individual student menu 5. Export grade book as txt file 6. Quit Enter your option: 1 Highest grade: 99 1. Display highest score of all grades 2. Display lowest score of all grades 3. Display entire grade book 4. Go to individual student menu 5. Export grade book as txt file 6. Quit Enter your option: 2 Lowest grade: 58 1. Display highest score of all grades 2. Display lowest score of all grades 3. Display entire grade book 4. Go to individual student menu 5. Export grade book as txt file 6. Quit

Lec2 HW1 HW3 HW4 76 HW5 88 68 94 88 93 60 66 92 Enter your option: 3 ID: Labi Lab2 1234 72 1235 70 1236 1237 69 1238 93 58 1. Display highest score of all grades 2. Display lowest score of all grades 3. Display entire grade book 4. Go to individual student menu 5. Export grade book as txt file 6. Quit Enter your option: 4 Enter student ID: 123456 Student not found.. 1. Display highest score of all grades 2. Display lowest score of all grades 3. Display entire grade book 4. Go to individual student menu 5. Export grade book as txt file 6. Quit Enter your option: 4 Enter student ID: 1234 7. Display all the lab grades and average lab score 8. Display all the lecture grades and average lecture score 9. Display all the assignment grades and average assignment score 10. Display the letter grade 11. Back to main menu Enter your option: 7 ID# Labi Lab2 Lab3 Avg 1234 72 76 70 7. Display all the lab grades and average lab score 8. Display all the lecture grades and average lecture score 9. Display all the assignment grades and average assignment score 10. Display the letter grade 11. Back to main menu 62

Avg 87 HW5 Avg 1234 88 88 88 84 Enter your option: 8 ID# Leci Lec2 Lec3 Lec4 1234 88 62 7. Display all the lab grades and average lab score 8. Display all the lecture grades and average lecture score 9. Display all the assignment grades and average assignment score 10. Display the letter grade 11. Back to main menu Enter your option: 9 ID HW1 HW2 HW3 HW4 92 68 7. Display all the lab grades and average lab score 8. Display all the lecture grades and average lecture score 9. Display all the assignment grades and average assignment score 10. Display the letter grade 11. Back to main menu Enter your option: 10 Letter grade: B 7. Display all the lab grades and average lab score 8. Display all the lecture grades and average lecture score 9. Display all the assignment grades and average assignment score 10. Display the letter grade 11. Back to main menu Enter your option: 12 Invalid entry 7. Display all the lab grades and average lab score 8. Display all the lecture grades and average lecture score 9. Display all the assignment grades and average assignment score 10. Display the letter grade 11. Back to main menu Enter your option: 11 1. Display highest score of all grades 2. Display lowest score of all grades 3. Display entire grade book 4. Go to individual student menu 5. Export grade book as txt file 6. Quit

Enter your option: 5 Success... 1. Display highest score of all grades 2. Display lowest score of all grades 3. Display entire grade book 4. Go to individual student menu 5. Export grade book as txt file 6. Quit Enter your option: 7 Invalid entry 1. Display highest score of all grades 2. Display lowest score of all grades 3. Display entire grade book 4. Go to individual student menu 5. Export grade book as txt file 6. Quit Enter your option: 6

HW1 HW2 HW3 HW4 HW5 Avg B gradebook.bt 1 ID# Labi Lab2 Lab3 Leci Lec2 Lec3 Lec4 2 1234 72 76 62 88 61 62 87 88 92 88 68 88 77 3 1235 94 70 87 68 83 71 75 93 99 88 78 80 82 1236 60 66 91 72 69 75 69 61 68 80 96 99 75 1237 92 69 74 88 87 64 85 90 66 90 64 84 79 1238 93 58 95 85 90 83 88 74 59 58 96 62 78 mo