Delete all the nodes from a doubly linked list that are smaller than a given value in C++
In this tutorial, we are going to learn how to delete all prime nodes from a doubly linked list.
Let's see the steps to solve the problem.
Write struct with data, prev and next pointers.
Write a function to insert the node into the doubly linked list.
Initialize the doubly linked list with dummy data.
Iterate over the doubly linked list. Find whether the current node data is less than given value or not.
If the current data is less than the given value, then delete the node.
Write a function to delete the node. Consider the following three cases while deleting the node.
If the node is head node, then move the head to next node.
If the node is middle node, then link the next node to the previous node
If the node is end node, then remove the previous node link.
Example
Let's see the code.
Live Demo
#include using namespace std; struct Node { int data; Node *prev, *next; }; void insertNode[Node** head_ref, int new_data] { Node* new_node = [Node*]malloc[sizeof[struct Node]]; new_node->data = new_data; new_node->prev = NULL; new_node->next = [*head_ref]; if [[*head_ref] != NULL] { [*head_ref]->prev = new_node; } [*head_ref] = new_node; } void deleteNode[Node** head_ref, Node* del] { if [*head_ref == NULL || del == NULL] { return; } if [*head_ref == del] { *head_ref = del->next; } if [del->next != NULL] { del->next->prev = del->prev; } if [del->prev != NULL] { del->prev->next = del->next; } free[del]; return; } void deleteSmallerNodes[Node** head_ref, int K] { Node* temp = *head_ref; Node* next; while [temp != NULL] { next = temp->next; if [temp->data < K] { deleteNode[head_ref, temp]; } temp = next; } } void printLinkedList[Node* head] { while [head != NULL] { cout data next; } } int main[] { Node* head = NULL; insertNode[&head, 1]; insertNode[&head, 2]; insertNode[&head, 3]; insertNode[&head, 4]; insertNode[&head, 10]; insertNode[&head, 11]; insertNode[&head, 12]; int K = 10; cout 3 -> 2 -> 1 -> Linked List after deletion: 12 -> 11 -> 10 ->Conclusion
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