Compilare: main.cpp: In function 'int main()': main.cpp:40:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("bfs.in", "r", stdin); ^ main.cpp:41:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("bfs.out", "w", stdout); ^ main.cpp:44:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d %d", &N, &M, &S), S --; ^ main.cpp: In member function 'void Graph::readGraph(int, int, bool)': main.cpp:12:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &x, &y); ^