duanna3634 2016-08-14 16:49

# 恐慌：Golang中的索引超出范围错误

In this program, I'm trying to calculate the shortest path between any two squares on chess board according to the moves of the knight, I checked few websites they say something about finding out the length, I ddint quiet understand how to work with.I'm encountering a error saying "panic:index out of range" Can anybody help me out..!! please

``````package main

import (
"bufio"
"fmt"
"os"
"sort"
"strings"
)

var heightcurrstack int
var currentSource string
var currentDest string
var currentDestn int
var PosMoves [8]int

func main() {

file, err := os.Open("chessin.txt")
if err != nil {
fmt.Println(err)
}
defer file.Close()
scanner := bufio.NewScanner(file)
for scanner.Scan() {
strs := strings.Split(scanner.Text(), ",")

currentSource = strs[0]
currentDest = strs[1]
IsValid(currentSource)
toNumber(currentSource)
IsValid(currentDest)
currentDestn = toNumber(currentDest)
}

}
func IsValid(b string) bool {

if b[0] <= 'H' && b[0] >= 'A' && b[1] <= '8' && b[1] >= '1' {
return true
}
return false
}

func toNumber(s string) int {
var Number int

if len(s) != 2 {
fmt.Println("Invalid Input", s, ".")
}
Number = int(s[0]-'A')*8 + int(s[1]-'0')
return Number
}

func ToString(n int) string {
n--
return string((n/8)+65) + string((n%8)+49)

}

func PossibleMoves(n int) [8]int {

a := ToString(n)
isval := IsValid(a)

if isval == true {
if IsValid(string(a[0]+1) + string(a[1]+2)) {
PosMoves[0] = toNumber(string(a[0]+1) + string(a[1]+2))
}
if IsValid(string(a[0]+1) + string(a[1]-2)) {
PosMoves[1] = toNumber(string(a[0]+1) + string(a[1]-2))
}
if IsValid(string(a[0]-1) + string(a[1]+2)) {
PosMoves[2] = toNumber(string(a[0]-1) + string(a[1]+2))
}
if IsValid(string(a[0]-1) + string(a[1]-2)) {
PosMoves[3] = toNumber(string(a[0]-1) + string(a[1]-2))
}
if IsValid(string(a[0]+2) + string(a[1]+1)) {
PosMoves[4] = toNumber(string(a[0]+2) + string(a[1]+1))
}
if IsValid(string(a[0]+2) + string(a[1]-1)) {
PosMoves[5] = toNumber(string(a[0]+2) + string(a[1]-1))
}
if IsValid(string(a[0]-2) + string(a[1]+1)) {
PosMoves[6] = toNumber(string(a[0]-2) + string(a[1]+1))
}
if IsValid(string(a[0]-2) + string(a[1]-1)) {
PosMoves[7] = toNumber(string(a[0]-2) + string(a[1]-1))
}
}

sort.Sort(sort.Reverse(sort.IntSlice(PosMoves[0:8])))
return PosMoves
}
var visithistory [64]bool

func IsvisitedNode(currentSource int) bool {

visithistory[currentSource] = true

if visithistory[currentSource] == true {

return false

}
return true

}

type stack []int

func (s stack) Push(currentSource int) stack {
return append(s, currentSource)
}

func (s stack) Pop() ([]int) {
heightcurrstack := len(s)

return s[0:heightcurrstack]
}

func dfstraversal(currentSource int) {

var currentchildren [8]int
copy(PosMoves[:], currentchildren[:])
s := make(stack, 0)

if IsvisitedNode(currentSource) == true {

var j int = 0
for j < len(currentchildren) {
currentchildren[j+1] = currentSource
}
} else  if IsvisitedNode(currentSource) == false { //condition 1:previously not visited
if heightcurrstack > 6 { //condition 2: if the number of moves are more than 6
tracesuccessfulpath()
}

if currentSource == currentDestn { //condition 3 : if the destination  posititon is found
tracesuccessfulpath()
}
s = s.Push(currentSource)

s = s.Push(currentchildren[0])

currentchildren[0] = currentSource

if currentSource == currentDestn {
tracesuccessfulpath()
}

}

PossibleMoves(currentSource)
dfstraversal(currentSource)

}

func tracesuccessfulpath() {

s := make(stack, 0)
s.Pop()

var Path []string

for _,x := range s {
Path := append(Path, ToString(x))

fmt.Println(Path)
}

}
``````
• 写回答

#### 1条回答默认 最新

• douhui5953 2016-08-14 18:43
关注

You are passing a 0 or 1 char string to your "toNumber(s string)" function. That's why is panicking.

This is probably caused because you don't have the proper information in chessin.txt. When you split it in `strs := strings.Split(scanner.Text(), ",")` is not finding what you are expecting

本回答被题主选为最佳回答 , 对您是否有帮助呢?
评论

#### 悬赏问题

• ¥100 求购一套带接口实现实习自动签到打卡
• ¥50 MacOS 使用虚拟机安装k8s