package main
import (
"errors"
"fmt"
"strconv"
)
type List struct {
Length int
Head *Node
}
type Node struct {
NextNode *Node
Value int
}
func (list *List) IsEmpty() bool {
return list.Length == 0
}
func (list *List) Append(value int) {
list.Length += 1
if list.Head == nil {
list.Head = &Node{Value: value}
return
}
lastNode := list.Head
for lastNode.NextNode != nil {
lastNode = lastNode.NextNode
}
lastNode.NextNode = &Node{Value: value}
}
func (list *List) Delete(index int) error {
if index + 1 > list.Length {
return errors.New("index out of range")
}
list.Length -= 1
if index == 0{
list.Head = list.Head.NextNode
return nil
}
indexNode := list.Head
for i := index; i > 1; i-- {
indexNode = indexNode.NextNode
}
if indexNode.NextNode != nil {
indexNode.NextNode = indexNode.NextNode.NextNode
} else {
indexNode.NextNode = nil
}
return nil
}
func (list *List) String() string {
var ret string
node := list.Head
for node.NextNode != nil {
ret += strconv.Itoa(node.Value) + ","
node = node.NextNode
}
ret += strconv.Itoa(node.Value)
return ret
}
func (list *List) Insert(index, value int) error {
if index + 1 > list.Length {
return errors.New("index out of range")
}
list.Length++
if index == 0{
list.Head = &Node{Value:value, NextNode:list.Head}
return nil
}
indexNode := list.Head
for i := index; i > 1; i-- {
indexNode = indexNode.NextNode
}
tempNode := &Node{Value: value, NextNode: indexNode.NextNode}
indexNode.NextNode = tempNode
return nil
}
func main() {
a := List{}
for i := 0; i < 10; i++ {
a.Append(i)
}
fmt.Println(a.String())
if err := a.Insert(9, 99); err != nil{
fmt.Println(err)
}
fmt.Println(a.String())
}
