Added some Algorithms of Linked Lists in C and C++

Algorithms/CircularSLL.cpp

@@ -0,0 +1,248 @@
+#include <iostream>
+using namespace std;
+
+template <class T>
+struct Node
+{
+    T data;
+    Node<T> *next;
+};
+
+template <class T>
+class LinkedList
+{
+public:
+    Node<T> *head;
+    LinkedList()
+    {
+        head = NULL;
+    }
+    void insertionHead()
+    {
+        Node<T> *temp = new Node<T>;
+        cout << "\nenter the value to be inserted " << endl;
+        T n;
+        cin >> n;
+        temp->data = n;
+        if (head == NULL)
+        {
+            head = temp;
+            head->next = head;
+        }
+        else
+        {
+            Node<T> *loop = head;
+            while (loop->next != head)
+                loop = loop->next;
+            temp->next = head;
+            head = temp;
+            loop->next = head;
+        }
+    }
+    void insertionTail()
+    {
+        Node<T> *temp = new Node<T>;
+        cout << "\nenter the value to be inserted " << endl;
+        T n;
+        cin >> n;
+        temp->data = n;
+        if (head == NULL)
+        {
+            head = temp;
+            head->next = head;
+        }
+        else
+        {
+            Node<T> *p = head;
+            while (p->next != head)
+                p = p->next;
+            temp->next = head;
+            p->next = temp;
+        }
+    }
+    void deletionHead()
+    {
+        if (head != NULL)
+        {
+            if (head->next == head)
+            {
+                Node<T> *delnode = head;
+                cout << "element deleted " << head->data;
+                head = NULL;
+                delete delnode;
+            }
+            else
+            {
+                Node<T> *delnode = head;
+                cout << "element deleted " << head->data;
+                Node<T> *loop = head;
+                while (loop->next != head)
+                    loop = loop->next;
+                head = head->next;
+                loop->next = head;
+                delnode->next = NULL;
+                delete delnode;
+            }
+        }
+        else
+        {
+            cout << "List empty";
+        }
+    }
+    void deletionTail()
+    {
+        if (head != NULL)
+        {
+            if (head->next == head)
+            {
+                Node<T> *delnode = head;
+                cout << "element deleted " << head->data;
+                head = NULL;
+                delete delnode;
+            }
+            else
+            {
+                Node<T> *temp = head;
+                while (temp->next->next != head)
+                    temp = temp->next;
+                cout << "element deleted " << temp->next->data;
+                Node<T> *delnode = temp->next;
+                delete delnode;
+                temp->next = head;
+            }
+        }
+        else
+        {
+            cout << "List empty";
+        }
+    }
+    void search()
+    {
+        if (head == NULL)
+            cout << "\nList empty";
+        else
+        {
+            cout << "\nenter the value to be searched " << endl;
+            T x;
+            cin >> x;
+            Node<T> *temp = head;
+            bool found = false;
+            do
+            {
+                if (temp->data == x)
+                    found = true;
+                temp = temp->next;
+            } while (temp != head);
+
+            if (found)
+                cout << "\nElement found in linked list";
+            else
+                cout << "\nElement not found in linked list";
+        }
+    }
+    void reverse()
+    {
+        if (head == NULL)
+        {
+            cout << "\nList is empty.";
+            return;
+        }
+        else if (head->next == head)
+        {
+            cout << "\nList only has one element";
+            return;
+        }
+
+        Node<T> *prev = NULL;
+        Node<T> *temp = head;
+        Node<T> *next;
+        do
+        {
+            next = temp->next;
+            temp->next = prev;
+            prev = temp;
+            temp = next;
+        } while (temp != head);
+        head->next = prev;
+        head = prev;
+        cout << "\nThe list has been reversed";
+    }
+    void display()
+    {
+        Node<T> *temp = head;
+        while (temp != NULL)
+        {
+            cout << temp->data << "->";
+            if (temp->next == head)
+                break;
+            temp = temp->next;
+        }
+        cout << "!!!";
+    }
+    void alt_display()
+    {
+        Node<T> *temp = head;
+        while (temp != NULL)
+        {
+            cout << temp->data << "->";
+            if (temp->next == head || temp->next->next == head)
+                break;
+            temp = temp->next->next;
+        }
+        cout << "!!!";
+    }
+};
+
+int main()
+{
+    LinkedList<int> l;
+    int ch;
+    char cont;
+    do
+    {
+        cout << "\nEnter your choice among following " << endl;
+        cout << "1.Insert an element at beginning" << endl;
+        cout << "2.Insert an element at end" << endl;
+        cout << "3.Delete an element from beginning" << endl;
+        cout << "4.Delete an element from end" << endl;
+        cout << "5.Search the list" << endl;
+        cout << "6.Reverse the list" << endl;
+        cout << "7.Display alternate elements of Linked List" << endl;
+        cout << "8.Display Linked List\n"
+             << endl;
+        cin >> ch;
+        switch (ch)
+        {
+            int val;
+        case 1:
+            l.insertionHead();
+            break;
+        case 2:
+            l.insertionTail();
+            break;
+        case 3:
+            l.deletionHead();
+            break;
+        case 4:
+            l.deletionTail();
+            break;
+        case 5:
+            l.search();
+            break;
+        case 6:
+            l.reverse();
+            break;
+        case 7:
+            l.alt_display();
+            break;
+        case 8:
+            l.display();
+            break;
+        default:
+            cout << "\nInvalid choice " << endl;
+        }
+        cout << "\n\nContinue?(y/n)" << endl;
+        cin >> cont;
+    } while (cont == 'y' || cont == 'Y');
+    return 0;
+}

Algorithms/DoublyLinkedList.c

@@ -0,0 +1,72 @@
+/* CREATING A SIMPLE DOUBLY LINKED LIST */
+/* DBLINK.C */
+
+# include <stdio.h>
+# include <malloc.h>
+
+struct Double
+{
+	int info;
+	struct Double *next;
+	struct Double *previous;
+};
+
+int num ;
+struct Double start;
+void Doubly_link_list (struct Double *);
+void display (struct Double *);
+
+/* Function creates a simple doubly linked list */
+
+void Doubly_link_list(struct Double *node)
+{
+	char ch;
+	start.next = NULL;  /* Empty list */
+	start.previous = NULL;
+	node = &start;      /* Point to the start of the list */
+	num = 0;
+	printf("\n Input choice n for break: ");
+	ch = getchar();
+
+	while( ch != 'n')
+	{
+		node->next = (struct Double *) malloc(sizeof(struct Double));
+		node->next->previous = node;
+		node = node->next;
+		printf("\n Input the values of the node : %d: ", (num+1));
+		scanf("%d", &node->info);
+		node->next = NULL;
+		fflush(stdin);
+		printf("\n Input choice n for break: ");
+		ch = getchar();
+		num ++;
+	}
+	printf("\n Total nodes = %d", num);
+}
+
+/* Display the list */
+
+void display (struct Double *node)
+{
+	node = start.next;
+
+	do {
+		printf("\n 0x%x", node);
+		printf(" %d", node->info);
+		node = node->next;
+	} while (node->next);  /* Show value of last node only one time */
+
+	do {
+		printf("\n 0x%x", node );
+		printf(" %d", node->info);
+		node = node->previous;
+	} while (node->previous);
+}
+
+int main()
+{
+	struct Double *node = (struct Double *) malloc(sizeof(struct Double));
+	Doubly_link_list(node);
+	printf("\n Created doubly linked list is as follows\n");
+	display(node);
+}