在 Scanner 输入中使用类、参数、对象

Question

I have a class City.java and State.java with automatically generated constructors, getters and setters (if needed I can add them to the question).

In Main.java my task is to get information with Scanner as input and make objects with all the information written in.

Data input for each object is needed to be taken out in separate methods that will be eventually called from main method. Each of these methods must return the object that fills. It's allowed to only one object of class Scanner .

public Class City { 
   private String name;
   private Bigdecimal surface;
   //+constructor , + getters and setters
}
public Class State {
   private String name;
   private City city;
 //+constructor , + getters and setters
}

public class Main {

    public static City city (Scanner scanner) {
       System.out.println("Store City name : ");
       String cityName = scanner.nextLine();
       System.out.println("Store City surface : ");
       BigDecimal citySurface = scanner.nextBigDecimal();

    return new City(cityName,citySurface);
    }

    public static State state (Scanner scanner){
      System.out.println("Store State name : ");
      String stateName = scanner.nextLine();

I'm lost at this point. The task is that I should return new State with parameters (stateName,City) but I can't figure out how to pass the previously entered city here as a parameter.

      }


  public static void main(String[] args) {
    Scanner mainScanner = new Scanner (System.in);
  }
}

Answer 1

You could try this:

public class Main {

  public static City city (Scanner scanner) {
   System.out.println("Store City name : ");
   String cityName = scanner.nextLine();
   System.out.println("Store City surface : ");
   BigDecimal citySurface = scanner.nextBigDecimal();

   return new City(cityName,citySurface);
  }

  public static State state (Scanner scanner, City city){
    System.out.println("Store State name : ");
    String stateName = scanner.nextLine();
    //Do stuff here with city e.g. city.getName()
    return new State(stateName, city);
  }

  public static void main(String[] args) {
    Scanner mainScanner = new Scanner (System.in);
    City myCity = city(scanner);
    state(mainScanner, myCity);
    //I'm sure you could also do this code in shorthand like below because of the callstack order.
    //state(mainScanner, city(scanner));
  }

}

You just need to pass the city object through to the state and then handle the code that should happen once you have it. To be honest I don't think you should have those methods there in the Main class and as statics and stuff, but that is another issue entirely.