Making a method which returns an ArrayList-CodePudding

i cant figure out how i can make a method which returns an (updated) ArrayList. I want a method which asks for user input, make an object out of the input, and than put it in a list. I want the method to return this list to the main.

This is what i made in the main method:

public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    ArrayList<Doctor> listOfDoctors = new ArrayList<>();
    ArrayList<Examination> listOfExaminations = new ArrayList<>();
    ArrayList<Patient> listOfPatients = new ArrayList<>();      

while (true) {
        menu(); //shows options 1 to 5
        String option = scanner.nextLine();
        if (option.isEmpty()) {
            break;
        }
        if (option.equals("1")) {
            System.out.println("What is the name of the doctor?");
            String nameDoctor = scanner.nextLine();
            System.out.println("What is the doctor's specialisation?");
            String specialisationDoctor = scanner.nextLine();
            listOfDoctors.add(new Doctor(nameDoctor, specialisationDoctor));
            System.out.println("added!");
        }

I want to make a method of option 1 but i dont know how. This is what i tried:

public static ArrayList<> addDoctorToList(ArrayList<>) {
    ArrayList<Doctor> listOfDoctors = new Arraylist<>();
    Scanner scanner = new Scanner(System.in);
    
    System.out.println("What is the name of the doctor?");
    String nameDoctor = scanner.nextLine();
    System.out.println("What is the doctor's specialisation?");
    String specialisationDoctor = scanner.nextLine();
    listOfDoctors.add(new Doctor(nameDoctor, specialisationDoctor));
    System.out.println("added!");
    return listOfDoctors;

I hope someone could help me.

CodePudding user response：

There's 2 different things you can do :

the method takes an existing list, and add a Doctor to it (you can return it or just modify the existing ArrayList).

In this case, you need a name to your param, and don't create a new ArrayList:

public static ArrayList<> addDoctorToList(ArrayList<> listOfDoctors ) {
    Scanner scanner = new Scanner(System.in);
...

The method creates a new empty ArrayList, and don't need to be passed a param, so remove this type in the parenthesis:

public static ArrayList<> addDoctorToList() {
    ArrayList<Doctor> listOfDoctors = new Arraylist<>();
    Scanner scanner = new Scanner(System.in);
...

CodePudding user response：

Your method is not a type of Doctor list

Since you are returning a type of doctor object as your list type your method suppose to be the same.

Change this codes:

        public static ArrayList<> addDoctorToList(ArrayList<String> var) {
ArrayList<Doctor> listOfDoctors = new Arraylist

To:

         public static ArrayList<Doctor> addDoctorToList(ArrayList<String> var) {
ArrayList<Doctor> listOfDoctors = new Arraylist

CodePudding user response：

I guess could work a simple method like this below:

public static void insertDoctor(){
   System.out.println("What's the name of the doctor?");
   String nameDoctor=scanner.nextLine();
   System.out.println("What's the doctor's specislisaton?");
   String specialisationDoctor=scanner.nextLine();
   listOfDoctor.add(new Doctor(nameDoctor, specialisationDoctor));
   System.out.println("added!");
}

What do you think about?