Compilare: user.cpp: In function ‘void bf_dragons(std::vector<std::pair<int, int> >&)’: user.cpp:29:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k = 0; k < dragons.size(); ++k) ^ user.cpp: In function ‘int valid(int)’: user.cpp:51:15: warning: variable ‘lin’ set but not used [-Wunused-but-set-variable] int i, j, k, lin, col, new_lin, new_col, new_mat[MatrixSize][MatrixSize]; ^ user.cpp:51:20: warning: variable ‘col’ set but not used [-Wunused-but-set-variable] int i, j, k, lin, col, new_lin, new_col, new_mat[MatrixSize][MatrixSize]; ^