The linked list stores data in sequential storage, like arrays. Though the data are stored sequentially, the memory locations are not contiguous.
Unlike an array, the linked list can store data of different data types.
The below diagram represents the linked-list structure.
In C++ the linked list can be represented with a class and a Node class separately, which has two members, namely data and a next pointer which points to the next node.
InsertNode: In this article, insertion is done at the end of the list. Follow the steps to insert a node in the linked list.
- Let’s say, 4 is to be inserted on the existing linked list, i.e., 1 -> 2 -> 3.The resultant linked list will be 1 -> 2 -> 3 -> 4.
- To insert a new node traverse till the end of the list until NULL node is found.
- Create a new Node, and link the new node to the last node of the linked list.
DeleteNode: In this article, deletion is done using the index of the node. Follow the steps to delete a node:
- If the node to be deleted is the head node, store the head in temp variable. Then update head as head->next. Delete temp.
- If the index of the node to be deleted is greater than the length of the list then return from the function.
- Traverse till the node to be deleted. Delete the node, and link the previous node to the next node of the deleted node.
Below is the implementation of the above approach:
C++
// C++ program for the above approach #include <iostream> using namespace std; // Node class to represent // a node of the linked list. class Node { public: int data; Node* next; // Default constructor Node() { data = 0; next = NULL; } // Parameterised Constructor Node(int data) { this->data = data; this->next = NULL; } }; // Linked list class to // implement a linked list. class Linkedlist { Node* head; public: // Default constructor Linkedlist() { head = NULL; } // Function to insert a // node at the end of the // linked list. void insertNode(int); // Function to print the // linked list. void printList(); // Function to delete the // node at given position void deleteNode(int); }; // Function to delete the // node at given position void Linkedlist::deleteNode(int nodeOffset) { Node *temp1 = head, *temp2 = NULL; int ListLen = 0; if (head == NULL) { cout << "List empty." << endl; return; } // Find length of the linked-list. while (temp1 != NULL) { temp1 = temp1->next; ListLen++; } // Check if the position to be // deleted is greater than the length // of the linked list. if (ListLen < nodeOffset) { cout << "Index out of range" << endl; return; } // Declare temp1 temp1 = head; // Deleting the head. if (nodeOffset == 1) { // Update head head = head->next; delete temp1; return; } // Traverse the list to // find the node to be deleted. while (nodeOffset-- > 1) { // Update temp2 temp2 = temp1; // Update temp1 temp1 = temp1->next; } // Change the next pointer // of the previous node. temp2->next = temp1->next; // Delete the node delete temp1; } // Function to insert a new node. void Linkedlist::insertNode(int data) { // Create the new Node. Node* newNode = new Node(data); // Assign to head if (head == NULL) { head = newNode; return; } // Traverse till end of list Node* temp = head; while (temp->next != NULL) { // Update temp temp = temp->next; } // Insert at the last. temp->next = newNode; } // Function to print the // nodes of the linked list. void Linkedlist::printList() { Node* temp = head; // Check for empty list. if (head == NULL) { cout << "List empty" << endl; return; } // Traverse the list. while (temp != NULL) { cout << temp->data << " "; temp = temp->next; } } // Driver Code int main() { Linkedlist list; // Inserting nodes list.insertNode(1); list.insertNode(2); list.insertNode(3); list.insertNode(4); cout << "Elements of the list are: "; // Print the list list.printList(); cout << endl; // Delete node at position 2. list.deleteNode(2); cout << "Elements of the list are: "; list.printList(); cout << endl; return 0; } |
Output
Elements of the list are: 1 2 3 4 Elements of the list are: 1 3 4
Time Complexity: O(N)
Auxiliary Space: O(N)
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