Given the partial LinkedList class declaration below, select an expression to complete the empty method, which is designed to return true if the list contains no elements.
A)first != null
B)first == null
C)first.data == null
D)first.next == null

Question

Given the partial LinkedList class declaration below, select an expression to complete the empty method, which is designed to return true if the list contains no elements.  
A)first != null 
B)first == null 
C)first.data == null 
D)first.next == null

Quizplus · Accepted Answer

If the first node of the linked list is null, that means the list is empty and should return true. All other options check for properties of the first node or subsequent nodes, which could potentially be null or have null data even if the list is not completely empty.

Given the Partial LinkedList Class Declaration Below, Select an Expression