I am receiving a StackOverflow error when ever I run the program instead of finding the Knights Tour. Any idea what is causing this and how I can change my code around to actually find the Knights Tour and get rid of this error. Project is for my CS280 class and is due on Friday please help. Thanks!!
public class KnightsTourDriver {
public static void main (String[]args) {
KnightsTour tour1 = new KnightsTour;
tour1.findTour(1);
tour1.displayTour();
}
}
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 == 64)
{
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 && x >= 0 && y >= 0)
{
return true;
}
else return false;
}
/*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++;
break;
}
else isSafe = false;
break;
}
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++;
break;
}
else isSafe = false;
break;
}
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++;
break;
}
else isSafe = false;
break;
}
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++;
break;
}
else isSafe = false;
break;
}
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++;
break;
}
else isSafe = false;
break;
}
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++;
break;
}
else isSafe = false;
break;
}
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++;
break;
}
else isSafe = false;
break;
}
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++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case -1:
j--;
tryNextMove(a);
break;
case -2:
j--;
tryNextMove(a);
break;
case -3:
j--;
tryNextMove(a);
break;
case -4:
j--;
tryNextMove(a);
break;
case -5:
j--;
tryNextMove(a);
break;
case -6:
j--;
tryNextMove(a);
break;
case -7:
j--;
tryNextMove(a);
break;
case -8:
j--;
tryNextMove(a);
break;
}
}
public void tryNextMove(int m)
{
move(m++);
}
//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++;
}
}
}
}
