Compilare: user.cpp: In function ‘int main()’: user.cpp:53:105: warning: operation on ‘p’ may be undefined [-Wsequence-point] if (mat[q[++p][0] + dx[i]][q[p][1] + dy[i]] == '0' && !b[q[++p][0] + dx[i]][q[p][1] + dy[i]]) ^ user.cpp:55:58: warning: operation on ‘p’ may be undefined [-Wsequence-point] b[q[++p][0] + dx[i]][q[p][1] + dy[i]] = 1; ^ user.cpp:58:82: warning: operation on ‘p’ may be undefined [-Wsequence-point] d[q[++p][0] + dx[i]][q[p][1] + dy[i]] = 1 + d[q[++p][0]][q[p][1]]; ^