Compilare: user.cpp: In function ‘void bfs(int)’: user.cpp:25:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<graph[current_node].size();i++) ~^~~~~~~~~~~~~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:39:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sate.in", "r", stdin); ^ user.cpp:40:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sate.out", "w", stdout); ^ user.cpp:42:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m, &x, &y); ^ user.cpp:46:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &k, &l, &d); ^