Compilare: user.cpp: In function ‘int main()’: user.cpp:44:27: warning: suggest parentheses around arithmetic in operand of ‘|’ [-Wparentheses] M[i].push_back((i << 1) & ((1 << N) - 1) | 0); ^ user.cpp:45:27: warning: suggest parentheses around arithmetic in operand of ‘|’ [-Wparentheses] M[i].push_back((i << 1) & ((1 << N) - 1) | 1); ^ user.cpp:52:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < drum.size(); i++) ^