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root / semester_2 / assignments / assignment_05.cpp

assignment_05.cpp (4951B)

---

 /* Implement Doubly Linked List. Include functions for insertion, deletion and search of a number, reverse the list. */
 
 #include <iostream>
 using namespace std;
 
 typedef struct nodeType {
     int data;
     nodeType *prev = nullptr;
     nodeType *next = nullptr;
 } node;
 
 class DoublyLinkedList {
 private:
     node *head;
 
 public:
     DoublyLinkedList() { head = nullptr; }
 
     void insAtBegin() {
         node *newNode = new node;
         cout << "Enter the value: ";
         cin >> newNode->data;
         newNode->prev = nullptr;
         newNode->next = head;
         if (head != nullptr) head->prev = newNode;
         head = newNode;
     }
 
     void insAtEnd() {
         node *newNode = new node;
         cout << "Enter the value: ";
         cin >> newNode->data;
         newNode->next = nullptr;
         if (head == nullptr) {
             newNode->prev = nullptr;
             head = newNode;
         } else {
             node *temp = head;
             while (temp->next != nullptr) temp = temp->next;
             temp->next = newNode;
             newNode->prev = temp;
         }
     }
 
     void insAtPos() {
         int pos;
         cout << "Enter the position: ";
         cin >> pos;
         if (pos < 1) { cout << "Invalid Position!\n"; return; }
         if (pos == 1) { insAtBegin(); return; }
         node *temp = head;
         for (int i = 1; i < pos - 1 && temp != nullptr; i++) temp = temp->next;
         if (temp == nullptr) { cout << "Out of range!\n"; return; }
         node *newNode = new node;
         cout << "Enter the value: ";
         cin >> newNode->data;
         newNode->next = temp->next;
         newNode->prev = temp;
         if (temp->next != nullptr) temp->next->prev = newNode;
         temp->next = newNode;
     }
 
     void delAtBegin() {
         if (head == nullptr) { cout << "List is empty!\n"; return; }
         node *temp = head;
         head = head->next;
         if (head != nullptr) head->prev = nullptr;
         delete temp;
     }
 
     void delAtEnd() {
         if (head == nullptr) { cout << "List is empty!\n"; return; }
         if (head->next == nullptr) { delete head; head = nullptr; return; }
         node *temp = head;
         while (temp->next != nullptr) temp = temp->next;
         temp->prev->next = nullptr;
         delete temp;
     }
 
     void delAtPos() {
         if (head == nullptr) { cout << "List is empty!\n"; return; }
         int pos;
         cout << "Enter the position: ";
         cin >> pos;
         if (pos < 1) { cout << "Invalid Position!\n"; return; }
         if (pos == 1) { delAtBegin(); return; }
         node *temp = head;
         for (int i = 1; i < pos && temp != nullptr; i++) temp = temp->next;
         if (temp == nullptr) { cout << "Out of range!\n"; return; }
         if (temp->next != nullptr) temp->next->prev = temp->prev;
         if (temp->prev != nullptr) temp->prev->next = temp->next;
         delete temp;
     }
 
     void search() {
         if (head == nullptr) { cout << "List is empty!\n"; return; }
         int key, pos = 1;
         cout << "Enter the element to search: ";
         cin >> key;
         node *temp = head;
         while (temp != nullptr) {
             if (temp->data == key) { cout << "Found at position: " << pos << "\n"; return; }
             temp = temp->next;
             pos++;
         }
         cout << "Element not found.\n";
     }
 
     void reverse() {
         if (head == nullptr || head->next == nullptr) return;
         node *curr = head, *temp = nullptr;
         while (curr != nullptr) {
             temp = curr->prev;
             curr->prev = curr->next;
             curr->next = temp;
             curr = curr->prev;
         }
         if (temp != nullptr) head = temp->prev;
     }
 
     void display() {
         node *temp = head;
         cout << "List: nullptr  ";
         while (temp != nullptr) { cout << temp->data << "  "; temp = temp->next; }
         cout << "nullptr\n";
     }
 
     void printMenu() {
         cout << "1.insertAtBegin 2.insertAtEnd 3.insertAtPos 4.deleteAtBegin 5.deleteAtEnd \n"
              << "6.deleteAtPos 7.search 8.reverse 0.Display -1.Exit\n";
     }
 
     ~DoublyLinkedList() {
         node *temp;
         while (head != nullptr) { temp = head; head = head->next; delete temp; }
     }
 };
 
 int main() {
     DoublyLinkedList list;
     int choice;
 
     while (true) {
         list.printMenu();
         cout << "Enter your choice: ";
         cin >> choice;
 
         switch (choice) {
             case 1: list.insAtBegin(); break;
             case 2: list.insAtEnd(); break;
             case 3: list.insAtPos(); break;
             case 4: list.delAtBegin(); break;
             case 5: list.delAtEnd(); break;
             case 6: list.delAtPos(); break;
             case 7: list.search(); break;
             case 8: list.reverse(); break;
             case 0: list.display(); break;
             case -1: cout << "Exiting...\n"; return 0;
             default: cout << "Wrong choice. Try again.\n";
         }
     }
 }