Compilare: user.cpp: In function ‘void BFS(int)’: user.cpp:18:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j; ^ user.cpp: In function ‘int main()’: user.cpp:42:34: 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); ^ user.cpp:43:36: 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); ^ user.cpp:47:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d ", &N, &M, &Start); ^ user.cpp:53:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ", &x, &y); ^