Question

For the following given class,

class Node
{
  private T    data; // Entry in bag
  private Node next; // Link to next node

  private Node()
  {
   this(null, null);
  } // end constructor
  
  private Node(T dataPortion)
  {
   this(dataPortion, null);
  } // end constructor
  
  private Node(T dataPortion, Node nextNode)
  {
   data = dataPortion;
   next = nextNode;
  } // end constructor
} // end Node

which code correctly adds the first entry to an empty bag?

A		Node newNode = new Node(newEntry, null);   firstNode = newNode;
B		Node newNode = new Node(); newNode = newEntry; firstNode = newNode;
C		both a & b
D		none of the above

Answer 1

Node newNode = new Node(newEntry, null);  
firstNode = newNode;

option A is correct. it first creates a new Node with next pointer null, because this is a empty bag currently. Next it makes that node as the first node.

In option B, newEntry is an undeclared variable hence wrong.