Insert element in linkedlist - Implement in go

 This is 4th post on linked list, for previous post on linkedlist, please check posts from :

https://sreesindhusruthi.blogspot.com/2021/07/create-single-linked-list-in-golang.html

Insert is the function name to insert nodes in linked list:

func (ll *LinkedList) Insert(data int, position int){ }

Step1:  We need to have a Node with the data given. 

temp := new(Node)
temp.data = data

Step2: If linked list is empty then insert the temp Node as head of the linked list.

//This inserts new element as linked list is empty
if ll.head == nil{
   ll.head = temp
   return
}

Step3: If position is 0 then we need to update the linkedlist head to temp Node and update the current linked list reference.

//This inserts at beginning of the linked list.
if position == 0{
   temp.next = ll.head
   ll.head = temp
}

Step4: Loop till we reach the position we want to Insert  the Node, we need a variable currentNode to traverse till the desired position, update the currentNode for each iteration of the loop, we will compare the position with currentposition.

var currPosition int
currentNode := ll.head

for currPosition < position-1 && currentNode != nil {
   currentNode = currentNode.next
   currPosition ++
   //fmt.Println(currentNode.data, currPosition)
}

Step5: Once we are at the postion where we have to Insert the node update the linked list references.

Example linked list : 3-->7-->10-->NULL
ll.Insert(4, 2)
Expected output is : 3--> 7--> 4-->10--> NULL

To acheive expected output store Node with data 10 into existingNextNode.

existingNextNode := currentNode.next

Update currentNode links 7--> 4 .

currentNode.next = temp

then traverse currentNode from 7 to 4.

currentNode = currentNode.next

update currentNode next to existingNextNode 4-->10

currentNode.next = existingNextNode

//Update the links
existingNextNode := currentNode.next
currentNode.next = temp
currentNode = currentNode.next
currentNode.next = existingNextNode

Full code: