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Doubly-linked list/Element removal: Difference between revisions
→{{header|Nim}}
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Then deleting node2 yields:
1 -> 4
</pre>
=={{header|Nim}}==
This is a simplified version of code from [[Doubly-Linked List (traversal)]]
<lang Nim>type
DoublyLinkedList[T] = object
head, tail: Node[T]
Node[T] = ref TNode[T]
TNode[T] = object
next, prev: Node[T]
data: T
proc initDoublyLinkedList[T](): DoublyLinkedList[T] = discard
proc newNode[T](data: T): Node[T] =
new(result)
result.data = data
proc append[T](list: var DoublyLinkedList[T]; node: Node[T]) =
node.next = nil
node.prev = list.tail
if not list.tail.isNil: list.tail.next = node
list.tail = node
if list.head.isNil: list.head = node
proc remove[T](list: var DoublyLinkedList; node: Node[T]) =
if node == list.tail: list.tail = node.prev
if node == list.head: list.head = node.next
if not node.next.isNil: node.next.prev = node.prev
if not node.prev.isNil: node.prev.next = node.next
node.prev = nil
node.next = nil
proc `$`[T](list: DoublyLinkedList[T]): string =
var node = list.head
while not node.isNil:
if result.len > 0: result.add(" -> ")
result.add $node.data
node = node.next
var l = initDoublyLinkedList[int]()
let a = newNode(12)
let b = newNode(13)
let c = newNode(14)
let d = newNode(15)
l.append a
l.append b
l.append c
l.append d
echo l
l.remove b
echo l
l.remove a
echo l
l.remove d
echo l
l.remove c
echo l</lang>
{{out}}
<pre>12 -> 13 -> 14 -> 15
12 -> 14 -> 15
14 -> 15
14
</pre>
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