Golang Doubly Linked List

In a doubly-linked list, all nodes have a pointer to the node they are connected to, on either side of them, in the list. This means that each node is connected to two nodes, and we can traverse forward through to the next node or backward through to the previous node. 

Doubly linked lists allow insertion, deletion, and, obviously, traversing operations.

Golang Doubly Linked List Example

Let's create file named " doubly_linked_list.go" and add the following code to it:


package main

// importing fmt package
import (
	"fmt"
)

// Node class
type Node struct {
	property     int
	nextNode     *Node
	previousNode *Node
}

// LinkedList class
type LinkedList struct {
	headNode *Node
}

//AddToHead method of LinkedList
func (linkedList *LinkedList) AddToHead(property int) {
	var node = &Node{}
	node.property = property
	node.nextNode = nil
	if linkedList.headNode != nil {
		//fmt.Println(node.property)
		node.nextNode = linkedList.headNode
		linkedList.headNode.previousNode = node
	}

	linkedList.headNode = node

}

//NodeWithValue method of LinkedList
func (linkedList *LinkedList) NodeWithValue(property int) *Node {
	var node *Node
	var nodeWith *Node
	for node = linkedList.headNode; node != nil; node = node.nextNode {
		if node.property == property {
			nodeWith = node
			break
		}
	}
	return nodeWith
}

//AddAfter method of LinkedList
func (linkedList *LinkedList) AddAfter(nodeProperty int, property int) {
	var node = &Node{}
	node.property = property
	node.nextNode = nil

	var nodeWith *Node

	nodeWith = linkedList.NodeWithValue(nodeProperty)
	if nodeWith != nil {
		//fmt.Println(node.property)
		node.nextNode = nodeWith.nextNode
		node.previousNode = nodeWith
		nodeWith.nextNode = node
	}

}

//LastNode method of LinkedList
func (linkedList *LinkedList) LastNode() *Node {
	var node *Node
	var lastNode *Node
	for node = linkedList.headNode; node != nil; node = node.nextNode {
		if node.nextNode == nil {
			lastNode = node
		}
	}
	return lastNode
}

//AddToEnd method of LinkedList
func (linkedList *LinkedList) AddToEnd(property int) {
	var node = &Node{}
	node.property = property
	node.nextNode = nil

	var lastNode *Node

	lastNode = linkedList.LastNode()

	if lastNode != nil {

		lastNode.nextNode = node
		node.previousNode = lastNode
	}
}

//IterateList method of LinkedList
func (linkedList *LinkedList) IterateList() {

	var node *Node
	for node = linkedList.headNode; node != nil; node = node.nextNode {

		fmt.Println(node.property)
	}
}

//NodeBetweenValues method of LinkedList
func (linkedList *LinkedList) NodeBetweenValues(firstProperty int, secondProperty int) *Node {
	var node *Node
	var nodeWith *Node
	for node = linkedList.headNode; node != nil; node = node.nextNode {
		if node.previousNode != nil && node.nextNode != nil {
			if node.previousNode.property == firstProperty && node.nextNode.property == secondProperty {
				nodeWith = node
				break
			}
		}
	}
	return nodeWith
}

// main method
func main() {

	var linkedList LinkedList

	linkedList = LinkedList{}

	linkedList.AddToHead(1)
	linkedList.AddToHead(2)
	linkedList.AddToHead(3)
	linkedList.AddToHead(4)
	linkedList.AddToEnd(5)
	linkedList.AddAfter(1, 8)
	fmt.Println(linkedList.headNode.property)

	var node *Node
	node = linkedList.NodeBetweenValues(1, 5)
	fmt.Println(node.property)

}

The main() method creates a linked list. The nodes are added to the head and end. The node between values 1 and 5 is searched and its property is printed.

Run the following command to execute the doubly_linked_list.go file:

G:\GoLang\examples>go run doubly_linked_list.go
4
8

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