Eroare de compilare: user.cpp:15:12: error: expected primary-expression before ‘auto’ decltype(auto) at(int i, int j) { ^ user.cpp:15:12: error: expected ‘)’ before ‘auto’ user.cpp:15:3: error: expected unqualified-id before ‘decltype’ decltype(auto) at(int i, int j) { ^ user.cpp: In function ‘int get_num_fractions(int)’: user.cpp:27:19: error: ‘class BitMatrix’ has no member named ‘at’ if (fractions.at(k, k) == false) { ^ user.cpp:34:19: error: ‘class BitMatrix’ has no member named ‘at’ fractions.at(i, j) = false; ^ user.cpp:44:21: error: ‘class BitMatrix’ has no member named ‘at’ if (fractions.at(i, j) == true) ^