Create Doubly Linked List.cpp

code/data_structures/src/DoubleLinkedList/Doubly Linked List.cpp

@@ -0,0 +1,137 @@
+#include <iostream>
+
+class Node {
+public:
+    int data;
+    Node* next;
+    Node* prev;
+
+    Node(int data) {
+        this->data = data;
+        this->next = nullptr;
+        this->prev = nullptr;
+    }
+};
+
+class DLL {
+private:
+    Node* ptr;
+
+public:
+    DLL() {
+        ptr = nullptr;
+    }
+
+    void Insert(int data) {
+        Node* newnode = new Node(data);
+
+        if (ptr == nullptr) {
+            ptr = newnode;
+        }
+        else {
+            Node* current = ptr;
+            Node* prev = nullptr;
+            Node* nextptr = current->next;
+
+            while (current != nullptr && current->data < newnode->data) {
+                prev = current;
+                current = current->next;
+            }
+
+            if (current == nullptr) {
+                prev->next = newnode;
+                newnode->prev = prev;
+            }
+            else if (prev == nullptr) {
+                newnode->next = ptr;
+                ptr = newnode;
+            }
+            else {
+                prev->next = newnode;
+                newnode->next = current;
+                newnode->prev = prev;
+                current->prev = newnode;
+            }
+        }
+    }
+
+    void Display() {
+        Node* temp = ptr;
+        while (temp != nullptr) {
+            std::cout << temp->data << " <-> ";
+            temp = temp->next;
+        }
+        std::cout << "Null" << std::endl;
+    }
+
+    void Delete(int data) {
+        if (ptr == nullptr) {
+            std::cout << "List is Empty" << std::endl;
+            return;
+        }
+        else {
+            Node* current = ptr;
+            Node* prev = nullptr;
+
+            while (current != nullptr && current->data != data) {
+                prev = current;
+                current = current->next;
+            }
+
+            if (current != nullptr) {
+                if (prev == nullptr) {
+                    ptr = current->next;
+                    if (ptr != nullptr)
+                        current->prev = ptr;
+                }
+                else {
+                    prev->next = current->next;
+                    if (current->next != nullptr)
+                        current->next->prev = prev;
+                }
+            }
+            else {
+                std::cout << "Item not found in List" << std::endl;
+            }
+        }
+    }
+
+    bool Empty() {
+        return ptr == nullptr;
+    }
+};
+
+int main() {
+    DLL dll;
+
+    while (true) {
+        int choice;
+        std::cout << "\n1.Insert\n2.Delete\n3.Check Empty\n4.Exit\nEnter Choice: ";
+        std::cin >> choice;
+
+        if (choice == 1) {
+            int value;
+            std::cout << "Enter element to Insert: ";
+            std::cin >> value;
+            dll.Insert(value);
+            dll.Display();
+        }
+        else if (choice == 2) {
+            int value;
+            std::cout << "Enter element to Delete: ";
+            std::cin >> value;
+            dll.Delete(value);
+            dll.Display();
+        }
+        else if (choice == 3) {
+            std::cout << dll.Empty() << std::endl;
+        }
+        else if (choice == 4) {
+            break;
+        }
+    }
+
+    std::cout << "Program End" << std::endl;
+
+    return 0;
+}