public static void main(String[] args) {
    	FinalProject finalProject = new FinalProject();

        ArrayList<Person> list = new ArrayList<>(100);
        Scanner scanner = new Scanner(System.in);
        int choice;
        
        

        do {
            try {
            	System.out.println();
                System.out.println("Choose one of the options:");
                System.out.println("1- Enter the information of a faculty");
                System.out.println("2- Enter the information of a student");
                System.out.println("3- Print tuition invoice for a student");
                System.out.println("4- Print faculty information");
                System.out.println("5- Enter the information of a staff member");
                System.out.println("6- Print the information of a staff member");
                System.out.println("7- Delete a person");
                System.out.println("8- Exit Program");
                System.out.println();
                System.out.print("Enter your choice: ");
                System.out.println();

                choice = scanner.nextInt();

                switch (choice) {
                    case 1:
                        System.out.println("Enter the faculty info:");
                        System.out.print("Name: ");
                        String name = scanner.next();
                        
                        
                        String id;
                        do {
                            System.out.print("id: ");
                            id = scanner.next();
                            if (idformat(id)&&duplicateCheck(id,list)==false) {
                                break;
                            } else {System.out.println("Invalid ID format or duplicate id.");}                          
                        }while (1!=0);
                        
                        Scanner scanner2 = new Scanner(System.in);
                        
                        String rank;
                        do {
                            System.out.print("Rank: ");
                            rank = scanner2.next().toUpperCase();
                            if (rank.equals("PROFESSOR") || rank.equals("ADJUNCT")) {
                                break;
                            } else {System.out.println(rank+" is an invalid rank.");}                          
                        }while (1!=0);
                        
                        String department;
                        do {
                            System.out.print("Department: ");
                            department = scanner.next().toUpperCase();
                            if (department.equals("MATHEMATICS") || department.equals("ENGLISH") || department.equals("ENGINEERING")) {
                                break;
                            } else {System.out.println(department+" is an invalid department.");}                          
                        }while (1!=0);
                        
                        
                        
                        Faculty faculty = finalProject.new Faculty(name, id, department, rank);
                        list.add(faculty);
                        break;
                    case 2:
                        System.out.println("Enter the student info:");
                        System.out.print("Name: ");
                        String studentname = scanner.next();
                        
                        String studentid;
                        do {
                            System.out.print("Id: ");
                            studentid = scanner.next();
                            if (idformat(studentid)&&duplicateCheck(studentid,list)==false) {
                                break;
                            } else {System.out.println("Invalid ID format or duplicate id.");}                          
                        }while (1!=0);
                        
                        double gpa;
                        do {
                            System.out.print("Gpa: ");
                            gpa = scanner.nextDouble();
                            if (gpa >= 0 && gpa <= 4.5) {
                                break;
                            } else {System.out.println("Please enter a gpa between 0 and 4.5.");}                          
                        }while (1!=0);
                        
                        int credits;
                        do {
                            System.out.print("Credit Hours: ");
                            credits = scanner.nextInt();
                            if (credits >= 0 && credits <= 100) {
                                break;
                            } else {System.out.println("Please enter a reasonable number of credits.");}                          
                        }while (1!=0);
                        
                        	Student student = finalProject.new Student(studentname,studentid,gpa,credits);
                        	list.add(student);
                        
                        break;
                    case 3:
                        System.out.println("Enter the Student's id:");
                        Scanner scanner5 = new Scanner(System.in);
                        System.out.println("");
                        System.out.println("");
                        String object3 = scanner5.next();
                        boolean found3 = false;
                        for (Person person : list) {
                            if (person.getId().equals(object3)) {
                                found3 = true;
                                person.print();
                                break;
                            }}                      
                        if (!found3) {
                            System.out.println(object3 + " not found.");
                        }
                        break;
                    case 4:
                        System.out.println("Enter the Faculty’s id:");
                        String object = scanner.next();
                        boolean found = false;
                        for (Person person : list) {
                            if (person.getId().equals(object)) {
                                found = true;
                                person.print();
                                break;
                            }}                      
                        if (!found) {
                            System.out.println(object + " not found.");
                        }
                        break;
                    case 5:
                        System.out.println("Enter the Staff Member's info:");
                        System.out.println("");
                        System.out.print("Name: ");
                        String staffname = scanner.next();
                        
                        String staffid;
                        do {
                            System.out.print("Id: ");
                            staffid = scanner.next();
                            if (idformat(staffid)&&duplicateCheck(staffid,list)==false) {
                                break;
                            } else {System.out.println("Invalid ID format or duplicate id.");}                          
                        } while (1!=0);
                        
                        String staffdepartment;
                        do {
                            System.out.print("Department: ");
                            staffdepartment = scanner.next().toUpperCase();
                            if (staffdepartment.equals("MATHEMATICS") || staffdepartment.equals("ENGLISH") || staffdepartment.equals("ENGINEERING")) {
                                break;
                            } else {System.out.println(staffdepartment+" is an invalid department.");}                          
                        } while (1!=0);
                        
                        Scanner scanner3 = new Scanner(System.in);
                        String status;
                        do {
                            System.out.print("Status ('Full Time' or 'Part Time'): ");
                            status = scanner3.nextLine().toUpperCase();
                            if (status.equals("PART TIME") || status.equals("FULL TIME") ) {
                                break;
                            } else {System.out.println("Status must be 'Part Time' or 'Full time'.");}                          
                        } while (1!=0);
                        
                        Staff staff = finalProject.new Staff(staffname, staffid, staffdepartment,status);
                        list.add(staff);
                        break;
                    case 6:
                    	Scanner scanner4 = new Scanner(System.in);
                        System.out.println("Enter the Staff Member's id:");
                        System.out.println("");
                        String object2 = scanner4.next();
                        boolean found2 = false;
                        for (Person person : list) {
                            if (person.getId().equals(object2)) {
                                found2 = true;
                                person.print();
                                break;
                            }}                      
                        if (!found2) {
                            System.out.println(object2 + " not found.");
                        }
                        break;