Convert singly linked list into a circular linked list using Go (Golang)

Overview

Convert singly linked list into a circular linked list using Golang

Input singly linked list: 

"A" -> "B" -> "C" -> "D"

Output list that should be a circular linked list:

"A" -> "B" -> "C" -> "D"
^ |
|____________________|

Program

There are two important methods in this program

• ToCircular – converts a single linked list to a circular linked list

• IsCircular – checks if a linked list is a circular linked list

package main
import "fmt"
type node struct {
data string
next *node
}
type singlyLinkedList struct {
len int
head *node
}
func initList() *singlyLinkedList {
return &singlyLinkedList{}
}
func (s *singlyLinkedList) AddFront(data string) {
node := &node{
data: data,
}
if s.head == nil {
s.head = node
} else {
node.next = s.head
s.head = node
}
s.len++
return
}
func (s *singlyLinkedList) Traverse() error {
if s.head == nil {
return fmt.Errorf("TraverseError: List is empty")
}
current := s.head
for current != nil {
fmt.Println(current.data)
current = current.next
}
return nil
}
//Function to convert singly linked list to circular linked list
func (s *singlyLinkedList) ToCircular() {
current := s.head
for current.next != nil {
current = current.next
}
current.next = s.head
}
func (s *singlyLinkedList) IsCircular() bool {
if s.head == nil {
return true
}
current := s.head.next
for current.next != nil && current != s.head {
current = current.next
}
return current == s.head
}
func main() {
singleList := initList()
fmt.Printf("AddFront: D\n")
singleList.AddFront("D")
fmt.Printf("AddFront: C\n")
singleList.AddFront("C")
fmt.Printf("AddFront: B\n")
singleList.AddFront("B")
fmt.Printf("AddFront: A\n")
singleList.AddFront("A")
err := singleList.Traverse()
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("Size: %d\n", singleList.len)
singleList.ToCircular()
isCircular := singleList.IsCircular()
fmt.Printf("Is Circular: %t\n", isCircular)
}

Output

AddFront: D
AddFront: C
AddFront: B
AddFront: A
A
B
C
D
Size: 4
Is Circular: true