Question

what are append, pre-append and display current state of the list method in linkedList C#. Please explain with examples

Answer 1

What is LinkedList?

A LinkedList is a linear data structure which stores element in the non-contiguous location. The elements in a linked list are linked with each other using pointers. In C#, LinkedList is the generic type of collection which is defined in System.Collections.Generic namespace. It is a doubly linked list, therefore, each node points forward to the Next node and backward to the Previous node. It is a dynamic collection which grows, according to the need of your program. It also provides fast inserting and removing elements.

Constructors

A LinkedList class has 3 constructors which are used to create a LinkedList which are as follows:

1. LinkedList(): This constructor is used to create an instance of the LinkedList class that is empty.
2. LinkedList(IEnumerable): This constructor is used to create an instance of the LinkedList class that contains elements copied from the specified IEnumerable and has sufficient capacity to accommodate the number of elements copied.
3. LinkedList(SerializationInfo, StreamingContext): This constructor is used to create an instance of the LinkedList class that is serializable with the specified SerializationInfo and StreamingContext

Methods

• Append:Append adds data to a StringBuilder. Append method calls can be chained. This makes StringBuilder code more succinct and easier to read.StringBuilder
• AppendLine, the Framework places a newline sequence at the end of the specified string. This method makes code easier to read as well.

For example:

StringBuilder pp=new StringBuilder();

pp.AppendLine("Demo");

pp.Insert(0,Environment.NewLine);

• Prepend Method is used to add one value to the beginning of a sequence. This Prepend method like the Append method does not modify the elements of the sequence. Instead, it creates a copy of the sequence with the new element.

For example:

StringBuilder pp=new StringBuilder();

pp.Appendline("Demo1");

pp.Prepend(Environmet.NewLine);

• 4 different methods to add nodes

1. AddAfter: This method is used to add a new node or value after an existing node in the LinkedList.
2. AddBefore: This method is used to add a new node or value before an existing node in the LinkedList.
3. AddFirst() method insert the specified element at the beginning of the linked list
4. AddLast() method insert the specified element at the end of the linked list.

• 5 different methods to remove elements

1. Clear(): This method is used to remove all nodes from the LinkedList.
2. Remove(LinkedListNode): This method is used to remove the specified node from the LinkedList.
3. Remove(T): This method is used to remove the first occurrence of the specified value from the LinkedList.
4. RemoveFirst(): This method is used to remove the node at the start of the LinkedList.
5. RemoveLast(): This method is used to remove the node at the end of the LinkedList.

• Contains(T):This method is used to determine whether a value is in the LinkedList.

Example Program1:

The LinkedList is accessed by using a foreach loop or by using for loop.

This program show how to create a LinkedList

using System;

using System.Collections.Generic;

class FT {

    // Main Method

    static public void Main()

    {

        // Creating a linkedlist

        // Using LinkedList class

        LinkedList<String> my_list = new LinkedList<String>();

        // Adding elements in the LinkedList

        // Using AddLast() method

        my_list.AddLast("Apple");

        my_list.AddLast("Orange");

        my_list.AddLast("Pineapple");

        my_list.AddLast("Jackfruit");

        my_list.AddLast("Graphes");

        my_list.AddLast("Apple");

        Console.WriteLine("Best fruits for the health:");

        // Accessing the elements of

        // LinkedLis​​​​​​​t Using foreach loop

        foreach(string str in my_list)

        {

            Console.WriteLine(str);

        }

    }

}

Output

 Best fruits for the health: Apple Orange Pineapple Jackfruit Graphes Apple

Example Program2:

Program to illustrate how to remove elements from Linkedlist

using System;

using System.Collections.Generic;

class FT {

    // Main Method

    static public void Main()

    {

        // Creating a linkedlist

        // Using LinkedList class

        LinkedList<String> my_list = new LinkedList<String>();

        // Adding elements in the LinkedList

        // Using AddLast() method

        my_list.AddLast("Apple");

        my_list.AddLast("Orange");

        my_list.AddLast("Pineapple");

        my_list.AddLast("Jackfruit");

        my_list.AddLast("Graphes");

        my_list.AddLast(" Apple");

        // Inital number of elements

        Console.WriteLine("Best fruits for the health "+

                         "initially:");

        // Accessing the elements of

        // Linkedlist Using foreach loop

        foreach(string str in my_list)

        {

            Console.WriteLine(str);

        }

        // After using Remove(LinkedListNode)

        // method

        Console.WriteLine("Best fruits for the health"+

                         " in 2016:");

        my_list.Remove(my_list.First);

        foreach(string str in my_list)

        {

            Console.WriteLine(str);

        }

        // After using Remove(T) method

        Console.WriteLine("Best fruits for the health"+

                         " in 2017:");

        my_list.Remove("Rohit");

        foreach(string str in my_list)

        {

            Console.WriteLine(str);

        }

        // After using RemoveFirst() method

        Console.WriteLine("Best fruits for the health"+

                         " in 2018:");

        my_list.RemoveFirst();

        foreach(string str in my_list)

        {

            Console.WriteLine(str);

        }

        // After using RemoveLast() method

        Console.WriteLine("Best fruits for the health"+

                         " in 2019:");

        my_list.RemoveLast();

        foreach(string str in my_list)

        {

            Console.WriteLine(str);

        }

        // After using Clear() method

        my_list.Clear();

        Console.WriteLine("Number of fruits: {0}",

                                     my_list.Count);

    }

}

Output

 Best fruits for the health initially: Apple Orange Pineapple Jackfruit Graphes Apple Best fruits for the health in 2016: Orange Pineapple Jackfruit Graphes Apple Best fruits for the health in 2017: Orange Jackfruit Graphes Apple Best fruits for the health in 2018: Jackfruit Graphes Apple Best fruits for the health in 2019: Jackfruit Graphes Number of fruits: 0