Creating a very simple linked list

Question

I am trying to create a linked list just to see if I can  and I am having trouble getting my head around it   Does anyone have an example of a very simple implementation of Linked list using C    All the examples I have found so far are quite overdone

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I am giving an extract from the book  C  6 0 in a Nutshell by Joseph Albahari and Ben Albahari   Here   s a demonstration on the use of LinkedList   var tune   new LinkedList lt string gt     tune AddFirst   do       do tune AddLast   so       do - so tune AddAfter  tune First   re       do - re- so tune AddAfter  tune First Next   mi       do - re - mi- so tune AddBefore  tune Last   fa       do - re - mi - fa- so tune RemoveFirst       re - mi - fa - so tune RemoveLast       re - mi - fa LinkedListNode lt string gt  miNode   tune Find   mi    tune Remove  miNode      re - fa tune AddFirst  miNode      mi- re - fa foreach  string s in tune  Console WriteLine  s

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I have a doubly Linked List which can be used as a stack or a queue  If you look at the code and think about what it does and how it does it I bet you will understand everything about it  I am sorry but somehow I couldn t pate the full code here so I here is the link for the linkedlist also I got the binary tree in the solution   https   github com szabeast LinkedList and BinaryTree

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A Linked List  at its core is a bunch of Nodes linked together   So  you need to start with a simple Node class   public class Node       public Node next      public Object data      Then your linked list will have as a member one node representing the head  start  of the list   public class LinkedList       private Node head      Then you need to add functionality to the list by adding methods   They usually involve some sort of traversal along all of the nodes   public void printAllNodes         Node current   head      while  current    null                 Console WriteLine current data           current   current next            Also  inserting new data is another common operation   public void Add Object data        Node toAdd   new Node        toAdd data   data      Node current   head         traverse all nodes  see the print all nodes method for an example      current next   toAdd      This should provide a good starting point

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public class Node lt T gt        public T item      public Node lt T gt  next      public Node                 this next   null            class LinkList lt T gt        public Node lt T gt  head   get  set        public LinkList                 this head   null              public void AddAtHead T item                Node lt T gt  newNode   new Node lt T gt             newNode item   item          if  this head    null                        this head   newNode                    else                       newNode next   head              this head   newNode                       public void AddAtTail T item                Node lt T gt  newNode   new Node lt T gt             newNode item   item          if  this head    null                        this head   newNode                    else                       Node lt T gt  temp   this head              while  temp next    null                                temp   temp next                            temp next   newNode                       public void DeleteNode T item                if  this head item Equals item                         head   head next                    else                       Node lt T gt  temp   head              Node lt T gt  tempPre   head              bool matched   false              while    matched   temp item Equals item    amp  amp  temp next    null                                tempPre   temp                  temp   temp next                            if  matched                                tempPre next   temp next                            else                               Console WriteLine  Value not found                                        public bool searchNode T item                Node lt T gt  temp   this head          bool matched   false          while    matched   temp item Equals item    amp  amp  temp next    null                        temp   temp next                    return matched             public void DisplayList                 Console WriteLine  Displaying List             Node lt T gt  temp   this head          while  temp    null                        Console WriteLine temp item               temp   temp next

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Add a Node class  Then add a LinkedList class to implement the linked list Add a test class to execute the linked list  namespace LinkedListProject       public class Node               public Node next          public object data             public class MyLinkedList               Node head          public Node AddNodes Object data                        Node node   new Node                 if  node next    null                                node data   data                  node next   head                  head   node                            else                               while  node next    null                      node   node next                   node data   data                  node next   null                             return node                     public void printnodes                         Node current   head              while  current next    null                                Console WriteLine current data                   current   current next                            Console WriteLine current data                          TestClass      public class LinkedListExample               MyLinkedList linkedlist   new MyLinkedList             TestMethod          public void linkedlisttest                         linkedlist AddNodes  hello                linkedlist AddNodes  world                linkedlist AddNodes  now                linkedlist printnodes

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Dmytro did a good job  but here is a more concise version   class Program       static void Main string   args                LinkedList linkedList   new LinkedList 1            linkedList Add 2           linkedList Add 3           linkedList Add 4            linkedList AddFirst 0            linkedList Print                         public class Node       public Node Node next  Object value                this next   next          this value   value             public Node next      public Object value     public class LinkedList       public Node head       public LinkedList Object initial                head   new Node null  initial              public void AddFirst Object value                head   new Node head  value                          public void Add Object value                Node current   head           while  current next    null                        current   current next                     current next   new Node null  value              public void Print                 Node current   head           while  current    null                        Console WriteLine current value               current   current next

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Here is a good implementation    It is short  but implemented Add x   Delete x   Contain x  and Print    It avoid special process when add to empty list or delete the first element  While most of other examples did special process when delete the first element  The list can contain any data type   using System   class Node lt Type gt    LinkedList lt Type gt         Why inherit from LinkedList  A  We need to use polymorphism      public Type value      public Node Type value    this value   value      class LinkedList lt Type gt           Node lt Type gt  next      This member is treated as head in class LinkedList  but treated as next element in class Node           lt summary gt  if x is in list  return previos pointer of x   We can see any class variable as a pointer           if not found  return the tail of the list   lt  summary gt      protected LinkedList lt Type gt  Previos Type x                LinkedList lt Type gt  p   this          point to head         for    p next    null  p   p next              if  p next value Equals x                   return p                   find x  return the previos pointer          return p                           not found  p is the tail                 lt summary gt  return value  true   success   false   x not exist  lt  summary gt      public bool Contain Type x    return Previos x  next    null   true   false             lt summary gt  return value  true   success   false   fail to add  Because x already exist            lt  summary gt     why return value  If caller want to know the result  they don t need to call Contain x  before  the action waste time      public bool Add Type x                LinkedList lt Type gt  p   Previos x           if  p next    null                 Find x already in list             return false          p next   new Node lt Type gt  x           return true                 lt summary gt  return value  true   success   false   x not exist  lt  summary gt      public bool Delete Type x                LinkedList lt Type gt  p   Previos x           if  p next    null              return false            Node lt Type gt  node   p next          p next   p next next            node Dispose             GC dispose automatically          return true            public void Print                 Console Write  List              for  Node lt Type gt  node   next  node    null  node   node next              Console Write node value ToString                   Console WriteLine            class Test       static void Main                 LinkedList lt int gt  LL   new LinkedList lt int gt             if   LL Contain 0      Empty list             Console WriteLine  0 is not exist             LL Print            LL Add 0           Add to empty list         LL Add 1   LL Add 2      attach to tail         LL Add 2           duplicate add  2 is tail          if  LL Contain 0     Find existed element which is head             Console WriteLine  0 is exist             LL Print            LL Delete 0        Delete head         LL Delete 2        Delete tail         if   LL Delete 0      Delete non-exist element             Console WriteLine  0 is not exist             LL Print            Console ReadLine               By the way  the implementation in  http   www functionx com csharp1 examples linkedlist htm have some problem    Delete   will fail when there is only 1 element   Throw exception at line  Head Next   Current Next   because Current is null   Delete position  will fail when deleting first element  In other words  call Delete 0  will fail

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Here is one with IEnumerable and a Recursive Reverse method though it is no faster than the while loop in the Reverse method both are O n       public class LinkedList lt T gt    IEnumerable       private Node lt T gt   head   null       public Node lt T gt  Add T value                var node   new Node lt T gt   Value   value            if   head    null                         head   node                    else                       var current    head              while  current Next    null                                current   current Next                            current Next   node    new head                    return node             public T Remove Node lt T gt  node                if   head    null              return node Value           if   head    node                         head    head Next              node Next   null              return node Value                     var current    head          while  current Next    null                        if  current Next    node                                current Next   node Next                  return node Value                             current   current Next                     return node Value             public void Reverse                 Node lt T gt  prev   null          var current    head           if  current    null              return           while  current    null                        var next   current Next              current Next   prev              prev   current              current   next                      head   prev             public void ReverseRecurisve                 reverseRecurive  head  null              private void reverseRecurive Node lt T gt  current  Node lt T gt  prev                if  current Next    null                         head   current               head Next   prev              return                     var next   current Next          current Next   prev          reverseRecurive next  current              public IEnumerator lt T gt  Enumerator                 var current    head          while  current    null                        yield return current Value              current   current Next                       public IEnumerator GetEnumerator                 return Enumerator             public class Node lt T gt        public T Value   get  set        public Node lt T gt  Next   get  set

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public class DynamicLinkedList        private class Node               private object element          private Node next           public object Element                       get   return this element                set   this element   value                       public Node Next                       get   return this next                set   this next   value                       public Node object element  Node prevNode                        this element   element              prevNode next   this                     public Node object element                        this element   element              next   null                       private Node head      private Node tail      private int count       public DynamicLinkedList                 this head   null          this tail   null          this count   0             public void AddAtLastPosition object element                if  head    null                        head   new Node element               tail   head                    else                       Node newNode   new Node element  tail               tail   newNode                     count               public object GetLastElement                 object lastElement   null          Node currentNode   head           while  currentNode    null                        lastElement   currentNode Element              currentNode   currentNode Next                     return lastElement             Testing with   static void Main string   args        DynamicLinkedList list   new DynamicLinkedList        list AddAtLastPosition 1       list AddAtLastPosition 2       list AddAtLastPosition 3       list AddAtLastPosition 4       list AddAtLastPosition 5        object lastElement   list GetLastElement        Console WriteLine lastElement

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I am a beginner and this helped me   class List       private Element Root      First you create the class List which will contain all the methods  Then you create the Node-Class  I will call it Element  class Element       public int Value      public Element Next      Then you can start adding methods to your List class  nbsp Here is a  add  method for example   public void Add int value        Element newElement   new Element        newElement Value   value       Element rootCopy   Root      Root   newElement      newElement Next   rootCopy       Console WriteLine newElement Value

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I ve created the following LinkedList code with many features  It is available for public under the CodeBase github public repo    Classes   Node and LinkedList  Getters and Setters  First and Last   Functions   AddFirst data   AddFirst node   AddLast data   RemoveLast    AddAfter node  data   RemoveBefore node   Find node   Remove foundNode   Print LinkedList   using System  using System Collections Generic   namespace Codebase       public class Node               public object Data   get  set            public Node Next   get  set             public Node                                public Node object Data  Node Next   null                        this Data   Data              this Next   Next                       public class LinkedList               private Node Head          public Node First                       get   gt  Head              set                               First Data   value Data                  First Next   value Next                                   public Node Last                       get                               Node p   Head                    Based partially on https   en wikipedia org wiki Linked list                 while  p Next    null                      p   p Next    traverse the list until p is the last node The last node always points to NULL                   return p                            set                               Last Data   value Data                  Last Next   value Next                                   public void AddFirst Object data  bool verbose   true                        Head   new Node data  Head               if  verbose  Print                       public void AddFirst Node node  bool verbose   true                        node Next   Head              Head   node              if  verbose  Print                       public void AddLast Object data  bool Verbose   true                        Last Next   new Node data               if  Verbose  Print                       public Node RemoveFirst bool verbose   true                        Node temp   First              Head   First Next              if  verbose  Print                return temp                     public Node RemoveLast bool verbose   true                        Node p   Head              Node temp   Last               while  p Next    temp                  p   p Next               p Next   null              if  verbose  Print                 return temp                     public void AddAfter Node node  object data  bool verbose   true                        Node temp   new Node data               temp Next   node Next              node Next   temp               if  verbose  Print                       public void AddBefore Node node  object data  bool verbose   true                        Node temp   new Node data                Node p   Head               while  p Next    node    Finding the node before                               p   p Next                             temp Next   p Next    same as    node             p Next   temp               if  verbose  Print                       public Node Find object data                        Node p   Head               while  p    null                                if  p Data    data                      return p                   p   p Next                            return null                     public void Remove Node node  bool verbose   true                        Node p   Head               while  p Next    node                                p   p Next                             p Next   node Next              if  verbose  Print                       public void Print                         Node p   Head              while  p    null    LinkedList iterator                               Console Write p Data                         p   p Next    traverse the list until p is the last node The last node always points to NULL                            Console WriteLine                        Using  yogihosting answer when she used the Microsoft built-in LinkedList and LinkedListNode to answer the question  you can achieve the same results   using System  using System Collections Generic  using Codebase   namespace Cmd       static class Program               static void Main string   args                        var tune   new LinkedList      Using custom code instead of the built-in LinkedList lt T gt              tune AddFirst  do       do             tune AddLast  so       do - so             tune AddAfter tune First   re       do - re- so             tune AddAfter tune First Next   mi       do - re - mi- so             tune AddBefore tune Last   fa       do - re - mi - fa- so             tune RemoveFirst       re - mi - fa - so             tune RemoveLast       re - mi - fa             Node miNode   tune Find  mi      Using custom code instead of the built in LinkedListNode             tune Remove miNode      re - fa             tune AddFirst miNode      mi- re - fa

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simple c  program to implement Single Link List with operations AddItemStart  AddItemEnd  RemoveItemStart  RemoveItemEnd and DisplayAllItems   using System      using System Collections Generic      using System Linq      using System Text      using System Threading Tasks       namespace SingleLinkedList               class Program                       Node head              Node current              int counter   0              public Program                                 head   new Node                    current   head                            public void AddStart object data                                Node newnode   new Node                    newnode next   head next                  newnode data   data                  head next   newnode                  counter                              public void AddEnd object data                                Node newnode   new Node                    newnode data   data                  current next   newnode                  current   newnode                  counter                              public void RemoveStart                                 if  counter  gt  0                                        head next   head next next                      counter--                                    else                                       Console WriteLine  No element exist in this linked list                                                 public void RemoveEnd                                 if  counter  gt  0                                        Node prevNode   new Node                        Node cur   head                      while  cur next    null                                                prevNode   cur                          cur   cur next                                            prevNode next   null                                    else                                       Console WriteLine  No element exist in this linked list                                                 public void Display                                 Console Write  Head - gt                     Node curr   head                  while  curr next    null                                        curr   curr next                      Console WriteLine curr data ToString                                                 public class Node                               public object data                  public Node next                            static void Main string   args                                Program p   new Program                    p AddEnd 2                   p AddStart 1                   p AddStart 0                   p AddEnd 3                   p Display                    p RemoveStart                    Console WriteLine  Removed node from Start                    p Display                    Console WriteLine  Removed node from End                    p RemoveEnd                    p Display                    Console ReadKey

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public class Node       private Object data       public Node next  get set        public Node Object data            this data   data              public class Linkedlist         Node head       public void Add Node n             n Next   this Head      this Head   n             using    LinkedList sample   new LinkedList    sample add new Node  first     sample Add new Node  second

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Based on what  jjnguy said  and fixing the bug in his PrintAllNodes    here s the full Console App example   public class Node       public Node next      public Object data     public class LinkedList       private Node head       public void printAllNodes                 Node current   head          while  current    null                        Console WriteLine current data               current   current next                       public void AddFirst Object data                Node toAdd   new Node             toAdd data   data          toAdd next   head           head   toAdd             public void AddLast Object data                if  head    null                        head   new Node                 head data   data              head next   null                    else                       Node toAdd   new Node                toAdd data   data               Node current   head              while  current next    null                                current   current next                             current next   toAdd                     class Program       static void Main string   args                Console WriteLine  Add First             LinkedList myList1   new LinkedList             myList1 AddFirst  Hello            myList1 AddFirst  Magical            myList1 AddFirst  World            myList1 printAllNodes             Console WriteLine             Console WriteLine  Add Last             LinkedList myList2   new LinkedList             myList2 AddLast  Hello            myList2 AddLast  Magical            myList2 AddLast  World            myList2 printAllNodes             Console ReadLine

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This one is nice      namespace ConsoleApplication1               T is the type of data stored in a particular instance of GenericList      public class GenericList lt T gt                private class Node                          Each node has a reference to the next node in the list              public Node Next                 Each node holds a value of type T              public T Data                        The list is initially empty          private Node head   null              Add a node at the beginning of the list with t as its data value          public void AddNode T t                        Node newNode   new Node                newNode Next   head              newNode Data   t              head   newNode                        The following method returns the data value stored in the last node in            the list  If the list is empty  the default value for type T is            returned          public T GetFirstAdded                            The value of temp is returned as the value of the method                  The following declaration initializes temp to the appropriate                 default value for type T  The default value is returned if the                 list is empty              T temp   default T                Node current   head              while  current    null                                temp   current Data                  current   current Next                            return temp                      Test code   static void Main string   args           Test with a non-empty list of integers      GenericList lt int gt  gll   new GenericList lt int gt         gll AddNode 5       gll AddNode 4       gll AddNode 3       int intVal   gll GetFirstAdded           The following line displays 5      System Console WriteLine intVal       I encountered it on msdn here

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A linked list is a node-based data structure  Each node designed with two portions  Data  amp  Node Reference  Actually  data is always stored in Data portion  Maybe primitive data types eg Int  Float  etc or we can store user-defined data type also eg  Object reference  and similarly Node Reference should also contain the reference to next node  if there is no next node then the chain will end   This chain will continue up to any node doesn t have a reference point to the next node    Please find the source code from my tech blog - http   www algonuts info linked-list-program-in-java html  package info algonuts   import java util ArrayList  import java util Arrays  import java util Iterator  import java util List   class LLNode       int nodeValue      LLNode childNode       public LLNode int nodeValue            this nodeValue   nodeValue          this childNode   null           class LLCompute       private static LLNode temp      private static LLNode previousNode      private static LLNode newNode      private static LLNode headNode       public static void add int nodeValue            newNode   new LLNode nodeValue           temp   headNode          previousNode   temp          if temp    null              compute               else             headNode   newNode        Set headNode            private static void compute             if newNode nodeValue  lt  temp nodeValue         Sorting - Ascending Order             newNode childNode   temp              if temp    headNode                   headNode   newNode                else if previousNode    null                   previousNode childNode   newNode                        else                       if temp childNode    null                  temp childNode   newNode                  else                               previousNode   temp                  temp   temp childNode                  compute                                       public static void display             temp   headNode          while temp    null                System out print temp nodeValue                   temp   temp childNode                     public class LinkedList         Entry Point     public static void main String   args              First Set Input Values         List  lt Integer gt  firstIntList   new ArrayList  lt Integer gt  Arrays asList 50 20 59 78 90 3 20 40 98               Iterator lt Integer gt  ptr    firstIntList iterator            while ptr hasNext                 LLCompute add ptr next                System out println  Sort with first Set Values            LLCompute display            System out println   n               Second Set Input Values         List  lt Integer gt  secondIntList   new ArrayList  lt Integer gt  Arrays asList 1 5 8 100 91               ptr    secondIntList iterator            while ptr hasNext                 LLCompute add ptr next                System out println  Sort with first  amp  Second Set Values            LLCompute display            System out println

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The selected answer doesn t have an iterator  it is more basic  but perhaps not as useful    Here is one with an iterator enumerator  My implementation is based on Sedgewick s bag  see http   algs4 cs princeton edu 13stacks Bag java html  void Main         var b   new Bag lt string gt         b Add  bike        b Add  erasmus        b Add  kumquat        b Add  beaver        b Add  racecar        b Add  barnacle         foreach  var thing in b                Console WriteLine thing               Define other methods and classes here  public class Bag lt T gt    IEnumerable lt T gt        public Node lt T gt  first    first node in list      public class Node lt T gt                public T item          public Node lt T gt  next           public Node T item                        this item   item                        public void Add T item                Node lt T gt  oldFirst   first          first   new Node lt T gt  item           first next   oldFirst             IEnumerator IEnumerable GetEnumerator                 return GetEnumerator               public IEnumerator lt T gt  GetEnumerator                 return new BagEnumerator lt T gt  this              public class BagEnumerator lt V gt    IEnumerator lt T gt                private Node lt T gt   head          private Bag lt T gt   bag          private Node lt T gt   curNode            public BagEnumerator Bag lt T gt  bag                          bag   bag               head   bag first               curNode   default Node lt T gt                        public T Current                       get   return  curNode item                        object IEnumerator Current                       get   return Current                       public bool MoveNext                         if   curNode    null                                 curNode    head                  if   curNode    null                  return false                  return true                            if   curNode next    null              return false              else                                curNode    curNode next                  return true                                    public void Reset                          curNode   default Node lt T gt                          public void Dispose

[c#] Creating a very simple linked list

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