Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:19:14: error: ‘i’ was not declared in this scope for(i=2;i<=k;i++) ^ user.cpp:21:21: error: ‘a’ was not declared in this scope use[a[i]]++; ^ user.cpp:51:18: error: no match for ‘operator<’ (operand types are ‘std::ofstream {aka std::basic_ofstream<char>}’ and ‘int’) fout<nr<<'\n'; ^ user.cpp:51:18: note: candidate: operator<(int, int) <built-in> user.cpp:51:18: note: no known conversion for argument 1 from ‘std::ofstream {aka std::basic_ofstream<char>}’ to ‘int’ In file included from /usr/include/c++/5/bits/stl_algobase.h:64:0, from /usr/include/c++/5/bits/char_traits.h:39, from /usr/include/c++/5/ios:40, from /usr/include/c++/5/istream:38, from /usr/include/c++/5/sstream:38, from /usr/include/c++/5/complex:45, from /usr/include/c++/5/ccomplex:38, from /usr/include/x86_64-linux-gnu/c++/5/32/bits/stdc++.h:52, from user.cpp:1: /usr/include/c++/5/bits/stl_pair.h:220:5: note: candidate: template<class _T1, class _T2> constexpr bool std::operator<(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&) operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) ^ /usr/include/c++/5/bits/stl_pair.h:220:5: note: template argument deduction/substitution failed: user.cpp:51:23: note: ‘std::ofstream {aka std::basic_ofstream<char>}’ is not derived from ‘const std::pair<_T1, _T2>’ fout<nr<<'\n'; ^ In file included from /usr/include/c++/5/bits/stl_algobase.h:67:0, from /usr/include/c++/5/bits/char_traits.h:39, from /usr/include/c++/5/ios:40, from /usr/include/c++/5/istream:38, from /usr/include/c++/5/sstream:38, from /usr/include/c++/5/complex:45, from /usr/include/c++/5/ccomplex:38, from /usr/include/x86_64-linux-gnu/c++/5/32/bits/stdc++.h:52, from user.cpp:1: /usr/include/c++/5/bits/stl_iterator.h:298:5: note: candidate: template<class _Iterator> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&) operator<(const reverse_iterator<_Iterator>& __x, ^ /usr/include/c++/5/bits/stl_iterator.h:298:5: note: template argument deduction/substitution failed: user.cpp:51:23: note: ‘std::ofstream {aka std::basic_ofstream<char>}’ is not derived from ‘const std::reverse_iterator<_Iterator>’ fout<nr<<'\n'; ^ In file included from /usr/include/c++/5/bits/stl_algobase.h:67:0, from /usr/include/c++/5/bits/char_traits.h:39, from /usr/include/c++/5/ios:40, from /usr/include/c++/5/istream:38, from /usr/include/c++/5/sstream:38, from /usr/include/c++/5/complex:45,