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Write a function to delete a Linked List
• Difficulty Level : Basic
• Last Updated : 18 May, 2021

Algorithm For C/C++: Iterate through the linked list and delete all the nodes one by one. The main point here is not to access the next of the current pointer if the current pointer is deleted.
In Java and Python, automatic garbage collection happens, so deleting a linked list is easy. Just need to change head to null.

Implementation:

## C++

 `// C++ program to delete a linked list``#include ``using` `namespace` `std;` `/* Link list node */``class` `Node {``public``:``    ``int` `data;``    ``Node* next;``};` `/* Function to delete the entire linked list */``void` `deleteList(Node** head_ref)``{` `    ``/* deref head_ref to get the real head */``    ``Node* current = *head_ref;``    ``Node* next = NULL;` `    ``while` `(current != NULL)``    ``{``        ``next = current->next;``        ``free``(current);``        ``current = next;``    ``}` `    ``/* deref head_ref to affect the real head back``        ``in the caller. */``    ``*head_ref = NULL;``}` `/* Given a reference (pointer to pointer) to the head``of a list and an int, push a new node on the front``of the list. */``void` `push(Node** head_ref, ``int` `new_data)``{``    ``/* allocate node */``    ``Node* new_node = ``new` `Node();` `    ``/* put in the data */``    ``new_node->data = new_data;` `    ``/* link the old list off the new node */``    ``new_node->next = (*head_ref);` `    ``/* move the head to point to the new node */``    ``(*head_ref) = new_node;``}` `/* Driver code*/``int` `main()``{``    ``/* Start with the empty list */``    ``Node* head = NULL;` `    ``/* Use push() to construct below list``    ``1->12->1->4->1 */``    ``push(&head, 1);``    ``push(&head, 4);``    ``push(&head, 1);``    ``push(&head, 12);``    ``push(&head, 1);` `    ``cout << ``"Deleting linked list"``;``    ``deleteList(&head);` `    ``cout << ``"\nLinked list deleted"``;``}` `// This is code is contributed by rathbhupendra`

## C

 `// C program to delete a linked list``#include``#include``#include` `/* Link list node */``struct` `Node``{``    ``int` `data;``    ``struct` `Node* next;``};` `/* Function to delete the entire linked list */``void` `deleteList(``struct` `Node** head_ref)``{``   ``/* deref head_ref to get the real head */``   ``struct` `Node* current = *head_ref;``   ``struct` `Node* next;` `   ``while` `(current != NULL)``   ``{``       ``next = current->next;``       ``free``(current);``       ``current = next;``   ``}``  ` `   ``/* deref head_ref to affect the real head back``      ``in the caller. */``   ``*head_ref = NULL;``}` `/* Given a reference (pointer to pointer) to the head``  ``of a list and an int, push a new node on the front``  ``of the list. */``void` `push(``struct` `Node** head_ref, ``int` `new_data)``{``    ``/* allocate node */``    ``struct` `Node* new_node =``            ``(``struct` `Node*) ``malloc``(``sizeof``(``struct` `Node));` `    ``/* put in the data  */``    ``new_node->data  = new_data;``   ` `    ``/* link the old list off the new node */``    ``new_node->next = (*head_ref);``   ` `    ``/* move the head to point to the new node */``    ``(*head_ref)    = new_node;``}` `/* Driver program to test count function*/``int` `main()``{``    ``/* Start with the empty list */``    ``struct` `Node* head = NULL;``   ` `    ``/* Use push() to construct below list``     ``1->12->1->4->1  */``    ``push(&head, 1);``    ``push(&head, 4);``    ``push(&head, 1);``    ``push(&head, 12);``    ``push(&head, 1);  ``   ` `    ``printf``(``"\n Deleting linked list"``);``    ``deleteList(&head); ``   ` `    ``printf``(``"\n Linked list deleted"``);``}`

## Java

 `// Java program to delete a linked list``class` `LinkedList``{``    ``Node head; ``// head of the list` `    ``/* Linked List node */``    ``class` `Node``    ``{``        ``int` `data;``        ``Node next;``        ``Node(``int` `d) { data = d; next = ``null``; }``    ``}` `    ``/* Function deletes the entire linked list */``    ``void` `deleteList()``    ``{``        ``head = ``null``;``    ``}` `    ``/* Inserts a new Node at front of the list. */``    ``public` `void` `push(``int` `new_data)``    ``{``        ``/* 1 & 2: Allocate the Node &``                  ``Put in the data*/``        ``Node new_node = ``new` `Node(new_data);` `        ``/* 3. Make next of new Node as head */``        ``new_node.next = head;` `        ``/* 4. Move the head to point to new Node */``        ``head = new_node;``    ``}` `    ``public` `static` `void` `main(String [] args)``    ``{``        ``LinkedList llist = ``new` `LinkedList();``        ``/* Use push() to construct below list``           ``1->12->1->4->1  */` `        ``llist.push(``1``);``        ``llist.push(``4``);``        ``llist.push(``1``);``        ``llist.push(``12``);``        ``llist.push(``1``);` `        ``System.out.println(``"Deleting the list"``);``        ``llist.deleteList();` `        ``System.out.println(``"Linked list deleted"``);``    ``}``}``// This code is contributed by Rajat Mishra`

## Python3

 `# Python3 program to delete all``# the nodes of singly linked list` `# Node class`  `class` `Node:` `    ``# Function to initialise the node object``    ``def` `__init__(``self``, data):``        ``self``.data ``=` `data  ``# Assign data``        ``self``.``next` `=` `None`  `# Initialize next as null`  `# Constructor to initialize the node object``class` `LinkedList:` `    ``# Function to initialize head``    ``def` `__init__(``self``):``        ``self``.head ``=` `None` `    ``def` `deleteList(``self``):` `        ``# initialize the current node``        ``current ``=` `self``.head``        ``while` `current:``            ``prev ``=` `current.``next`  `# move next node` `            ``# delete the current node``            ``del` `current.data` `            ``# set current equals prev node``            ``current ``=` `prev` `        ``# In python garbage collection happens``        ``# therefore, only``        ``# self.head = None``        ``# would also delete the link list` `    ``# push function to add node in front of llist``    ``def` `push(``self``, new_data):` `        ``# Allocate the Node &``        ``# Put in the data``        ``new_node ``=` `Node(new_data)` `        ``# Make next of new Node as head``        ``new_node.``next` `=` `self``.head` `        ``# Move the head to point to new Node``        ``self``.head ``=` `new_node`  `# Use push() to construct below``# list 1-> 12-> 1-> 4-> 1``if` `__name__ ``=``=` `'__main__'``:` `    ``llist ``=` `LinkedList()``    ``llist.push(``1``)``    ``llist.push(``4``)``    ``llist.push(``1``)``    ``llist.push(``12``)``    ``llist.push(``1``)` `    ``print``(``"Deleting linked list"``)``    ``llist.deleteList()` `    ``print``(``"Linked list deleted"``)`  `# This article is provided by Shrikant13`

## C#

 `// C# program to delete a linked list``using` `System;``    ` `public` `class` `LinkedList``{``    ``Node head; ``// head of the list` `    ``/* Linked List node */``    ``class` `Node``    ``{``        ``public` `int` `data;``        ``public` `Node next;``        ``public` `Node(``int` `d)``        ``{``            ``data = d; next = ``null``;``        ``}``    ``}` `    ``/* Function deletes the entire linked list */``    ``void` `deleteList()``    ``{``        ``head = ``null``;``    ``}` `    ``/* Inserts a new Node at front of the list. */``    ``public` `void` `push(``int` `new_data)``    ``{``        ``/* 1 & 2: Allocate the Node &``                ``Put in the data*/``        ``Node new_node = ``new` `Node(new_data);` `        ``/* 3. Make next of new Node as head */``        ``new_node.next = head;` `        ``/* 4. Move the head to point to new Node */``        ``head = new_node;``    ``}` `    ``// Driver code``    ``public` `static` `void` `Main(String [] args)``    ``{``        ``LinkedList llist = ``new` `LinkedList();``        ``/* Use push() to construct below list``        ``1->12->1->4->1 */` `        ``llist.push(1);``        ``llist.push(4);``        ``llist.push(1);``        ``llist.push(12);``        ``llist.push(1);` `        ``Console.WriteLine(``"Deleting the list"``);``        ``llist.deleteList();` `        ``Console.WriteLine(``"Linked list deleted"``);``    ``}``}` `// This code has been contributed by Rajput-Ji`

## Javascript

 ``
Output
```Deleting linked list
Linked list deleted```

Time Complexity: O(n)
Auxiliary Space: O(1)

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