Question

. [Tests knowledge of data structures] Create your own linked list (do not use any of the classes provided in the Collections API). Implement the following two operations:

If you are using jdk1.4 or before:

void add(Object ob);

boolean find(Object ob);

String toString();

If you are using j2se5.0 and you know generic programming:

void add(T ob);

boolean find(T ob);

String toString()

The toString method should arrange the elements of the list in a comma-separated sequence, in the following format:

[elem0, elem1, elem2, …, elemN]

Test your linked list in a main method which does the following:

a. Creates an instance of your list and adds the following Strings to it:
“Straight”, “Bent”, “Equals”, “Well”, “Storm”

b. Uses your find function to search for the keys “Well” and “Strength”

c. Outputs both the input list and the search results to the consoleand output the results to the consoleby repeatedly using your add function to populate a new instance of your linked list with Strings, and then outputting to console the boolean result of searching for some String in this list.

Answer 1

//Linked list class
class LinkedList<T>{
    //Node class
    static class Node<T>{
        //Variable to store data of the node
        T data;
        //Variable to store next node
        Node next;
    }
    //head node
    Node head;

    //Methdo to add data to linked list
    public void add(T t){
        //If head is null, then make the new node as head
        if(head==null){
            head = new Node<T>();
            head.data = t;
            return;
        }
        //Traverse to end of the linked list
        Node<T> temp = head;
        while(temp.next!=null){
            temp = temp.next;
        }
        //Add a new node at the end of the linked list
        temp.next = new Node<T>();
        temp.next.data = t;
    }

    //Method to find the element in the linked list
    public boolean find(T obj){
        //Traverse through all the nodes in the linked list
        Node temp = head;
        while(temp!=null){
            //Check if data equals the node's data
            if(temp.data.equals(obj)){
                return true;
            }
            temp = temp.next;
        }
        return false;
    }

    //Method to print list of strings
    public String toString(){
        //If head is null, then return empty list
        if(head==null){
            return "[ ]";
        }
        String ans = "[";
        Node temp = head;
        //Traverse through the list and add to ans variable
        while(temp!=null){
            ans = ans+temp.data;
            if(temp.next!=null){
                ans=ans+",";
            }
            temp = temp.next;
        }
        return ans+"]";
    }
}

class Main{
    public static void main(String[] args) {
        LinkedList<String> ll = new LinkedList<>();
        System.out.println("LL is "+ll);
        System.out.println("Well found ? "+ll.find("Well"));
        System.out.println("Strength found ? "+ll.find("Strength"));
        ll.add("Straight");
        System.out.println("LL is "+ll);
        System.out.println("Well found ? "+ll.find("Well"));
        System.out.println("Strength found ? "+ll.find("Strength"));
        ll.add("Bent");
        System.out.println("LL is "+ll);
        System.out.println("Well found ? "+ll.find("Well"));
        System.out.println("Strength found ? "+ll.find("Strength"));
        ll.add("Equals");
        System.out.println("LL is "+ll);
        System.out.println("Well found ? "+ll.find("Well"));
        System.out.println("Strength found ? "+ll.find("Strength"));
        ll.add("Well");
        System.out.println("LL is "+ll);
        System.out.println("Well found ? "+ll.find("Well"));
        System.out.println("Strength found ? "+ll.find("Strength"));
        ll.add("Storm");
        System.out.println("LL is "+ll);
        System.out.println("Well found ? "+ll.find("Well"));
        System.out.println("Strength found ? "+ll.find("Strength"));

    }
}

OUTPUT :