Question

Hello i have overriden toString() method in my own class, but somehow the output is not exactly the one I wanted. Sorry for the newbie question but i cant figure out where the problem is, any hint / help is mostly appreciated. Thank you.

Myclass:

public class Country implements Comparable<Country>{
    private String name;
    private String capital;
    private int area;

    public Country(String a, String b, int c) {
        this.name = a;
        this.capital = b;
        this.area =c;
    }

    @Override
    public String toString(){
        return(this.name + " "+ this.capital+" " + this.area);
    }
}

DS:

private void  preorder(BinaryNode  <type>  a){
      if (a != null){
       System.out.println(a.toString());
       preorder(a.left);
       preorder(a.right );
      }
} 

App:

BinarySearchTree <Country> db = new BinarySearchTree<Country>();
    Country ob  = new Country("Romania", "Buc", 123);
    db.addNewElement(ob);
        ob  = new Country("Hungaria", "Bud", 50);
    db.addNewElement(ob);
        ob  = new Country("Vatican", "Vat", 1);
    db.addNewElement(ob);
    db.printAll();

output:

adt.BinaryNode@1e5e2c3
adt.BinaryNode@18a992f
adt.BinaryNode@4f1d0d

EDIT: fix after “chaitanya10” hint for msitake

DS:

private void  preorder(BinaryNode  <type>  a){
      if (a != null){
       System.out.println(a.elm.toString()); // ACCES the data in node not the hole node.
       preorder(a.left);
       preorder(a.right );
      }
} 

Answer 1

your method takes BinaryNode<type> as an argument, you are calling toString on brinaryNode<type> not COuntry. you have overriden toString() in Country not BinaryTree.
change it to

private void  preorder(Country a){
      if (a != null){
       System.out.println(a.toString());

      }
} 

OR
override toString() in BinaryNode.