Compilare: user.cpp: In function ‘int main()’: user.cpp:142:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(file_in,"r",stdin); ^ user.cpp:143:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(file_out,"w",stdout); ^ user.cpp:145:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n,&m,&g); ^ user.cpp:158:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &a, &b, &c); ^ user.cpp: In function ‘bool bfs()’: user.cpp:66:15: warning: ‘p’ may be used uninitialized in this function [-Wmaybe-uninitialized] Q[++p]=j; ^