LinkedList Java traverse and print

Question

I would really appreciate if you can help to answer to this question:

I have already created a custom linked list myself in a very standard way using Java. Below are

Answer 1

Your getData() in Node class returns an Object type. You need to cast it into a String so that it gets printed by println() properly.

System.out.println((String)tmp.getData());

should do the trick for you.

Answer 2

You need to override the toString() method on Node:

@Override
String toString() {
  String val = // however you want to represent your Node
  return val;
}

and print the node:

System.out.println(tmp);

Alternatively, have Node.getData() return a String if you know you are only going to store Strings -- change the Objects to String in the Node definition

Alternatively, you could use generics to specify the type of data inside the node

UPDATE: after a little more thought (provoked by comments), I see something amiss:

tmp.getData() should return a string (based on Node's single parameter ctor and that you are passing strings), but the output is about references to Node objects. Is it possible that linkedList.add re-sets the Node's obj member to a Node instead?

Answer 3

The LinkedList is of Objects, Objects toString method prints out the reference. If you want to print out the string you are going to have either change the LinkedList to a String/Generics or cast the print out like this:

String output = (String)tmp.getData();
System.out.println(output);

(you can do this in one line if you want).

Answer 4

Your linkedList class already creates the Nodes for you!

linkedList list = new linkedList();
list.add("foo");
list.add("bar");
Node tmp = lst.getHead();
while(tmp != null){
    System.out.println(tmp.getData());
    tmp = tmp.getNext();
}

Will print

foo
bar