Compilare: user.cpp: In constructor ‘TopologicalSort::TopologicalSort(std::vector<std::vector<int> >&)’: user.cpp:15:12: warning: ‘TopologicalSort::s_ix’ will be initialized after [-Wreorder] int V, s_ix; ^ user.cpp:14:17: warning: ‘std::vector<int> TopologicalSort::sorted’ [-Wreorder] vector<int> sorted; ^ user.cpp:16:5: warning: when initialized here [-Wreorder] TopologicalSort(vector<vector<int>>& g) : ^ user.cpp:14:17: warning: ‘TopologicalSort::sorted’ will be initialized after [-Wreorder] vector<int> sorted; ^ user.cpp:13:18: warning: ‘std::vector<bool> TopologicalSort::visited’ [-Wreorder] vector<bool> visited; ^ user.cpp:16:5: warning: when initialized here [-Wreorder] TopologicalSort(vector<vector<int>>& g) : ^ user.cpp: In function ‘int main()’: user.cpp:31:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in", "r", stdin); ^ user.cpp:32:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out", "w", stdout); ^ user.cpp:33:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int N, M; scanf("%d %d", &N, &M); ^ user.cpp:37:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^