Pointers Segmentation fault

[Tryce]

I don't understand why i get a segmentation fault when setting the pointer to the the S(outh) tile, but not for any of the other directions. Could someone help point me in the right direction..

#include <iostream>
#include <cstdlib>
#include <unistd.h>
#include <time.h>
#include "warp.h"
#include "color.h"
using namespace std;

namespace warp {

  // Allocate memory for the board, and set its pointers to adjacent cells.
  void init_board(struct tile ****board) {
   (*board) = (struct tile ***) malloc(Y*sizeof(struct tile **)); //rows
    for (int i=0; i<=Y; i++) {
      (*board)[i] = (struct tile **) malloc(X*sizeof(struct tile *));  //cols
        for (int j=0; j<=X; j++) {
          (*board)[i][j] = (struct tile *) malloc(sizeof(struct tile)); //grid
          if(i==Y || j==X || i==0 || j==0) { //walls
            (*board)[i][j]->is_wall=true;
          }
          else {
          (*board)[i][j]->N=(*board)[i-1][j];
          //(*board)[i][j]->S=(*board)[1+i][j]; //segmentation fault occurs
          (*board)[i][j]->E=(*board)[i][j+1];
          (*board)[i][j]->W=(*board)[i][j-1];   }
        }
    }
  }

[helios]

Good grief! Why is this necessary?!

tile *init_board(){
    tile *ret = new tile[X * Y];
    for (int i = 0; i < Y; i++){
        for (int j = 0; j < X; j++){
            if (i == Y - 1 || j == X - 1 || i == 0 || j == 0)
                board[i * X + j].is_wall = true;
            else{
                board[i * X + j].N = board + ((i - 1) * X + j);
                board[i * X + j].S = board + ((i + 1) * X + j);
                board[i * X + j].E = board + (i * X + (j + 1));
                board[i * X + j].W = board + (i * X + (j - 1));
            }
        }
    }
}