Given the Node class (partially shown below), select a statement to complete the recursive method descendants, which is designed to return the number of descendants of a node.
A)num = num + child.descendants();
B)num = num + child.descendants() + 1;
C)num = child.descendants();
D)num = num + child.children.size();

Question

Given the Node class (partially shown below), select a statement to complete the recursive method descendants, which is designed to return the number of descendants of a node.  
A)num = num + child.descendants(); 
B)num = num + child.descendants() + 1; 
C)num = child.descendants(); 
D)num = num + child.children.size();

Quizplus · Accepted Answer

In order to calculate the number of descendants of a node, we must traverse through all of its children and their children as well. Thus, for each child node, we will recursively call the descendants method and add its result to the current count (num). Since we are counting descendants, we must also add 1 to account for the child node itself. Therefore, the correct statement to complete the method is num = num + child.descendants() + 1.

Given the Node Class (Partially Shown Below), Select a Statement