Compilare: user.cpp: In function ‘int main()’: user.cpp:18:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] {for(i=0;i<v[c[in]].size();i++) ^ user.cpp:7:30: 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:8:31: 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:10:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n,&m,&s); ^ user.cpp:12:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] {scanf("%d%d",&x,&y); ^