Thread: HowTo increase 1 value to the pointer and pass by ref?

Code:

#include <stdio.h>
#include <stdlib.h>
#define maxM 50
#define maxN 50
#define bool short
#define true 1
#define false 0
const short dirt[][] = 
	{{2, 1}, {1, 2}, {-1, 2}, {-2, 1}, {-2, -1}, {-1, -2}, {1, -2}, {2, -1}};

/* global varibles */
short m, n, half_tree;
short jw[maxM][maxN];	// jw = jump way
bool exist_way;
/* End of global varibles */

void extra_find(short x, short y, short *depth)
{
	int new_x, new_y, i;
	for (i = 0; i < 8; i++) {
		new_x = x+dirt[i][0];
		new_y = y+dirt[i][1];
		if ((new_x >= 0) && (new_y < m) && (new_y >= 0) && (new_y < n))
			if (jw[new_x][new_y] == 0) {
				jw[new_x][new_y] = half_tree + *depth;
				if (*depth == m*n) {
					exist_way = true;
					exit(0);
				}
				else extra_find(new_x, new_y, &((*depth)++));
				jw[new_x][new_y] = 0;
			}
	}
}

void find(short x, short y, short *depth)
{
	short x_coord, y_coord, new_x, new_y, max_depth, i;
	bool expand;
	x_coord = x;
	y_coord = y;
	expand = false;
	for (i = 0; i < 8; i++) {
		new_x = x+dirt[i][0];
		new_y = y+dirt[i][1];
		if ((new_x >= 0) && (new_y < m) && (new_y >= 0) && (new_y < n))
			if (jw[new_x][new_y] == 0) {
				expand = true;
				jw[new_x][new_y] = *depth;
				if (*depth == m*n) exit(0);
				else if (*depth < half_tree)
					find(new_x, new_y, &((*depth)++));
				jw[new_x][new_y] = 0;
			}
	}
	if (!expand) {
		max_depth = *depth;
		extra_find(x_coord, y_coord, &max_depth);
	}
}

void double_bfs()
{
	short x_coord, y_coord, i, j;
	for (i = 0; i < m; i++)
		for (j = 0; j < n; j++)
			jw[i][j] = 0;
	for (x_coord = 0; x_coord < m; x_coord++)
		for (y_coord = 0; y_coord < n; y_coord++) {
			jw[x_coord][y_coord] = 1;
			find(x_coord, y_coord, 2);
		}
}

int main()
{
	FILE *fr, *fw;
	short i, j; 
	
	fr = fopen("horse.dat", "rt");
	fw = fopen("horse.out", "wt");
	fscanf(fr, "%d %d", &m, &n);
	half_tree = (int)((m*n)/2);
	double_bfs();
	if (exist_way)
		for (i = 0; i < m; i++) {
			for (j = 0; j < n; j++)
				fprintf(fw, "%4d", jw[i][j]);
			fprintf(fw, "\n");
		}
	else fprintf(fw, "No solution.");
	fclose(fr);
	fclose(fw);
	return 0;
}

Code:

horse.c:8: error: array type has incomplete element type
horse.c: In function ‘extra_find’:
horse.c:30: error: invalid lvalue in unary ‘&’
horse.c: In function ‘find’:
horse.c:52: error: invalid lvalue in unary ‘&’
horse.c: In function ‘double_bfs’:
horse.c:71: warning: passing argument 3 of ‘find’ makes pointer from integer without a cast

HowTo increase 1 value to the depth pointer and pass by ref in find and extra_find function? What's wrong in this instruction?
find(x_coord, y_coord, 2);