(i) A linked list is formed from the objects of the class given below:

class Node{
    double sal;
    Node next;
}

Write an algorithm or a method to add a node at the end of an existing linked list. The method declaration is as follows:

void addNode(Node ptr, double ss)

void addNode(Node ptr, double ss){
    if(ptr == null)
        ptr = new Node(ss);
    else if(ptr.next == null)
        ptr.next = new Node(ss);
    else
        ptr = ptr.next;
}

(ii) Answer the following questions from the diagram of a binary tree given below:

(a) Write the pre-order traversal of the above tree structure.
A→F→D→G→B→H→E

(b) Name the parent of the nodes D and B.
Parent of D is F.
Parent of B is A.

(c) State the level of nodes E and F when the root is at level 0.
Level of E is 3.
Level of F is 1.