Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:30: error: redeclaration of ‘std::set<int, std::less<int>, std::allocator<int> > s’ user.cpp:21: error: ‘std::set<int, std::less<int>, std::allocator<int> > s’ previously declared here user.cpp:9: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:10: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result