Merge pull request #3134 from bhutani2002/master

Middle of the Linked List Algorithm with all the required Linked List…

data_structures/Linked_list/CPP/MiddleOfTheLinkedList.cpp

@@ -0,0 +1,166 @@
+//A linked list is a linear data structure, in which the elements are not stored at contiguous memory locations!
+
+#include <iostream>
+using namespace std;
+
+//Node Structure
+class Node
+{
+    public:
+     int data;
+     Node *next;
+};
+
+//Linked List Functions
+class LinkedList
+{
+    private:
+     Node *first;
+    public:
+     LinkedList(){first=NULL;}
+     LinkedList(int A[],int n);
+     ~LinkedList();
+
+     void Display();
+     void Insert(int index,int x);
+     int Delete(int index);
+     int Length();
+     int Middle();
+};
+
+//Parameterized Constructor to create a Linked List
+LinkedList::LinkedList(int A[],int n)
+{
+     Node *last,*t;
+     int i=0;
+
+     first=new Node;
+     first->data=A[0];
+     first->next=NULL;
+     last=first;
+
+     for(i=1;i<n;i++)
+     {
+     t=new Node;
+     t->data=A[i];
+     t->next=NULL;
+     last->next=t;
+     last=t;
+ }
+}
+
+//Destructor
+LinkedList::~LinkedList()
+{
+     Node *p=first;
+     while(first)
+     {
+        first=first->next;
+        delete p;
+        p=first;
+     }
+}
+
+//Display of the Linked List
+void LinkedList::Display()
+{
+    Node *p=first;
+
+    while(p)
+    {
+        cout<<p->data<<" ";
+        p=p->next;
+    }
+    cout<<endl;
+}
+
+//Length of the Linked List
+int LinkedList::Length()
+{
+    Node *p=first;
+    int len=0;
+
+    while(p)
+    {
+        len++;
+        p=p->next;
+    }
+    return len;
+}
+
+//Inserting in a Linked List
+void LinkedList::Insert(int index,int x)
+{
+    Node *t,*p=first;
+
+    if(index <0 || index > Length())
+    return;
+    t=new Node;
+    t->data=x;
+    t->next=NULL;
+
+    if(index==0)
+    {
+        t->next=first;
+        first=t;
+    }
+ else
+ {
+    for(int i=0;i<index-1;i++)
+    {
+        p=p->next;
+    }
+    t->next=p->next;
+    p->next=t;
+ }
+}
+
+//Deletion in the Linked List
+int LinkedList::Delete(int index)
+{
+    Node *p,*q=NULL;
+    int x=-1;
+
+    if(index < 1 || index > Length())
+    return -1;
+    if(index==1)
+    {
+        p=first;
+        first=first->next;
+        x=p->data;
+        delete p;
+    }
+    else
+    {
+        p=first;
+        for(int i=0;i<index-1;i++)
+    {
+        q=p;
+        p=p->next;
+    }
+    q->next=p->next;
+    x=p->data;
+    delete p;
+ }
+ return x;
+}
+
+//Finding the middle element of the linked list. (If no. of elements even-> exact middle element   if even-> 2nd middle element)
+int LinkedList::Middle()
+{
+    Node *slow=first,*fast=first;
+    while(fast!=NULL && fast->next!=NULL)
+    {
+        slow=slow->next;
+        fast=fast->next->next;
+    }
+    return slow->data;
+}
+int main()
+{
+ int A[]={1,2,3,4,5};
+ LinkedList l(A,5);  //Sending the Array of elements to the Linked List
+ l.Display(); //Displaying the Linked List
+ cout<<endl<<"Middle element of the Linked List: "<<l.Middle()<<endl; //Printing the Middle of the Element.
+ return 0;
+}