检查是否并保持程序未使用的方法无效：array IndexOutOfBounds error。我不能继续看看我的实际执行骑士之旅是否因为这个错误而起作用。
import java.util.Arrays;
class KnightsTour {
static int the_board[][] = new int[8][8];
int the_tour[][] = new int [8][8];
int k,moves = 0;
int x = 0, y = 0;
int z, j = 1;
boolean tour_found, isSafe;
//fills 2D array with 0's
public KnightsTour()
{
for (int i = 0; i < 8; i++)
{
for (int r = 0; r < 8; r++)
{
the_board[i][r] = 0;
}
}
}
/*recursive method, checks how many moves were made if 16 were made tour finished,
else if not moves knight checks if the move is valid if not back tracks*/
public void findTour(int q)
{
if(moves == 68)
{
tour_found = true;
}
else move(q);
if(isSafe == true)
{
findTour(q++);
moves++;
}
else
if(isSafe == false)
{
findTour(q*(-1));
moves--;
}
}
//used to keep prevent arrayindexoutofbounds error
public boolean arrayInBounds(int x, int y)
{
if(x > 8 || y > 8)
{
return false;
}
else return true;
}
/*move method uses switch statement to decide which move the knight should make
based on a case number, negative case numbers back track knight. if statement checks
if the current array element is empty and the index is inbounds*/
public void move(int a)
{
switch (a)
{
case 1:
if(arrayInBounds(x+2, y+1) == true){
if(the_board[x+2][y+1] != 0){
the_board[x+2][y+1]=j;
j++;
}
}
else isSafe = false;
case 2:
if (arrayInBounds(x+1, y+2) == true){
if(the_board[x+1][y+2] != 0){
the_board[x+1][y+2]=j;
j++;
}
}
else isSafe = false;
case 3:
if(arrayInBounds(x-1, y+2) == true){
if(the_board[x-1][y+2] != 0){
the_board[x-1][y+2]=j;
j++;
}
}
else isSafe = false;
case 4:
if (arrayInBounds(x-2, y+1) == true){
if(the_board[x-2][y+1] != 0){
the_board[x-2][y+1]=j;
j++;
}
}
else isSafe = false;
case 5:
if(arrayInBounds(x-2, y-1) == true){
if(the_board[x-2][y-1] != 0){
the_board[x-2][y-1]=j;
j++;
}
}
else isSafe = false;
case 6:
if(arrayInBounds(x-1, y-2) == true){
if(the_board[x-1][y-2] != 0){
the_board[x-1][y-2]=j;
j++;
}
}
else isSafe = false;
case 7:
if(arrayInBounds(x+1, y-2) == true){
if(the_board[x+1][y-2] != 0){
the_board[x+1][y-2]=j;
j++;
}
}
else isSafe = false;
case 8:
if(arrayInBounds(x+2, y-1) == true){
if(the_board[x+2][y-1] != 0){
the_board[x+2][y-1]=j;
j++;
}
}
else isSafe = false;
case -1:
the_board[x-2][y-1]=0;
j--;
case -2:
the_board[x-1][y-2]=0;
j--;
case -3:
the_board[x+1][y-2]=0;
j--;
case -4:
the_board[x+2][y-1]=0;
j--;
case -5:
the_board[x+2][y+1]=0;
j--;
case -6:
the_board[x+1][y+2]=0;
j--;
case -7:
the_board[x-1][y+2]=0;
j--;
case -8:
the_board[x-2][y+1]=0;
j--;
}
}
//for loop to display tour once found//
public void displayTour()
{
int v = 1;
for (int i = 0; i < 8; i++)
{
for (int e = 0; e < 8; e++)
{
if(v % 8 == 0)
{
System.out.print(the_board[i][e] + "\t");
System.out.println("\n");
}
else
System.out.print(the_board[i][e] + "\t");
v++;
}
}
}
}
答案 0 :(得分：3)
您的arrayInBounds方法不正确。 8是无效索引，但您的方法会错误地将其报告为有效。此外，它不会检查0以下的无效索引。
更改您的方法以检查x或y是否大于或等于 8，并检查是否小于{{} 1}}。
答案 1 :(得分：0)
你的主板是一个二维阵列，8 x 8.但是，因为数组有0个基础，你的主板真的是这样的：
00 10 20 30 40 50 60 70
01 11 21 31 41 51 61 71
02 12 22 32 42 52 62 72
03 13 23 33 43 54 63 73
04 14 24 34 44 54 64 74
05 15 25 35 45 55 65 75
06 16 26 36 46 56 66 76
07 17 27 37 47 57 67 77
因此，如果允许值为8的indeces，它们实际上将位于第9个位置，因此超出范围。
因此，要查看数组是否超出范围，请检查索引是否大于或等于 8，或检查它是否大于7
或者，切换你的逻辑，以便检查它是否是 in-bounds 而不是越界。所以我建议改变你的方法：
public boolean arrayInBounds(int x, int y) {
if(x > 8 || y > 8) {
return false;
} else {
return true;
}
}
到此：
public boolean arrayInBounds(int x, int y) {
return (x < 8 && y < 8 && x >= 0 && y >= 0);
}