Compilare: user.cpp: In function ‘int main()’: user.cpp:152:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < events.size(); i++) { ^ user.cpp:128:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mst.in","r",stdin); ^ user.cpp:129:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mst.out","w",stdout); ^ user.cpp:131:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp: In member function ‘void quadFuction::read()’: user.cpp:30:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d",&u,&v,&a,&b,&c); ^