Golang Program to add the first node in a given linked list.

Example

Approach to solve this problem

Step 1 − Define a method that accepts the head of the linked list.

Step 2 − If head == nil, create a new node and return that node.

Step 3 − If head is not nil, then update the head of the input linked list.

Example

 Live Demo

package main
import "fmt"
type Node struct {
   value int
   next *Node
}
func NewNode(value int, next *Node) *Node{
   var n Node
   n.value = value
   n.next = next
   return &n
}
func TraverseLinkedList(head *Node){
   temp := head
   for temp != nil {
      fmt.Printf("%d ", temp.value)
      temp = temp.next
   }
   fmt.Println()
}
func AddFirstNode(head *Node, data int) *Node{
   if head == nil{
      head = NewNode(data, nil)
      return head
   }
   newNode := NewNode(data, nil)
   newNode.next = head
   return newNode
}
func main(){
   head := NewNode(30, NewNode(10, NewNode(40, NewNode(40, nil))))
   fmt.Printf("Input Linked list is: ")
   TraverseLinkedList(head)
   head = AddFirstNode(head, 5)
   fmt.Printf("After adding first node, linked list is: ")
   TraverseLinkedList(head)
}

Output

Input Linked list is: 30 10 40 40
After adding first node, linked list is: 5 30 10 40 40