Compilare: user.cpp: In member function ‘void Graph::Dfs(int, std::vector<bool>&)’: user.cpp:26:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < edges_[node].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:44:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.in","r",stdin); ^ user.cpp:45:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.out","w",stdout); ^ user.cpp:47:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &num_nodes, &num_edges); ^ user.cpp:51:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &first_node, &second_node); ^