Compilare: user.cpp: In function ‘void read()’: user.cpp:17:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %lld ", &x, &y); ^ user.cpp: In function ‘int main()’: user.cpp:32:32: 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:33:33: 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:37:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %lld %lld ", &n,&m,&s); ^