Main.cc: In function ‘int main()’: Main.cc:32:8: error: no match for ‘operator<’ (operand types are ‘std::ostream {aka std::basic_ostream}’ and ‘const char [12]’) cout<"Impossible!"; ~~~~^~~~~~~~~~~~~~ In file included from /usr/include/c++/7/regex:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:110, from Main.cc:1: /usr/include/c++/7/bits/regex.h:1004:5: note: candidate: template bool std::__cxx11::operator<(const std::__cxx11::sub_match<_BiIter>&, const std::__cxx11::sub_match<_BiIter>&) operator<(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs) ^~~~~~~~ /usr/include/c++/7/bits/regex.h:1004:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::__cxx11::sub_match<_BiIter>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/regex:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:110, from Main.cc:1: /usr/include/c++/7/bits/regex.h:1083:5: note: candidate: template bool std::__cxx11::operator<(std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const std::__cxx11::sub_match<_BiIter>&) operator<(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs, ^~~~~~~~ /usr/include/c++/7/bits/regex.h:1083:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/regex:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:110, from Main.cc:1: /usr/include/c++/7/bits/regex.h:1163:5: note: candidate: template bool std::__cxx11::operator<(const std::__cxx11::sub_match<_BiIter>&, std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&) operator<(const sub_match<_Bi_iter>& __lhs, ^~~~~~~~ /usr/include/c++/7/bits/regex.h:1163:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::__cxx11::sub_match<_BiIter>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/regex:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:110, from Main.cc:1: /usr/include/c++/7/bits/regex.h:1240:5: note: candidate: template bool std::__cxx11::operator<(const typename std::iterator_traits<_Iter>::value_type*, const std::__cxx11::sub_match<_BiIter>&) operator<(typename iterator_traits<_Bi_iter>::value_type const* __lhs, ^~~~~~~~ /usr/include/c++/7/bits/regex.h:1240:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘const char [12]’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/regex:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:110, from Main.cc:1: /usr/include/c++/7/bits/regex.h:1314:5: note: candidate: template bool std::__cxx11::operator<(const std::__cxx11::sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*) operator<(const sub_match<_Bi_iter>& __lhs, ^~~~~~~~ /usr/include/c++/7/bits/regex.h:1314:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::__cxx11::sub_match<_BiIter>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/regex:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:110, from Main.cc:1: /usr/include/c++/7/bits/regex.h:1391:5: note: candidate: template bool std::__cxx11::operator<(const typename std::iterator_traits<_Iter>::value_type&, const std::__cxx11::sub_match<_BiIter>&) operator<(typename iterator_traits<_Bi_iter>::value_type const& __lhs, ^~~~~~~~ /usr/include/c++/7/bits/regex.h:1391:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘const char [12]’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/regex:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:110, from Main.cc:1: /usr/include/c++/7/bits/regex.h:1471:5: note: candidate: template bool std::__cxx11::operator<(const std::__cxx11::sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&) operator<(const sub_match<_Bi_iter>& __lhs, ^~~~~~~~ /usr/include/c++/7/bits/regex.h:1471:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::__cxx11::sub_match<_BiIter>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/future:39:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:105, from Main.cc:1: /usr/include/c++/7/thread:281:3: note: candidate: bool std::operator<(std::thread::id, std::thread::id) operator<(thread::id __x, thread::id __y) noexcept ^~~~~~~~ /usr/include/c++/7/thread:281:3: note: no known conversion for argument 1 from ‘std::ostream {aka std::basic_ostream}’ to ‘std::thread::id’ In file included from /usr/include/c++/7/forward_list:38:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:104, from Main.cc:1: /usr/include/c++/7/bits/forward_list.h:1388:5: note: candidate: template bool std::operator<(const std::forward_list<_Tp, _Alloc>&, const std::forward_list<_Tp, _Alloc>&) operator<(const forward_list<_Tp, _Alloc>& __lx, ^~~~~~~~ /usr/include/c++/7/bits/forward_list.h:1388:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::forward_list<_Tp, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95:0, from Main.cc:1: /usr/include/c++/7/valarray:1186:1: note: candidate: template std::_Expr, typename std::__fun::result_type> std::operator<(const _Tp&, const std::valarray<_Tp>&) _DEFINE_BINARY_OPERATOR(<, __less) ^ /usr/include/c++/7/valarray:1186:1: note: template argument deduction/substitution failed: Main.cc:32:9: note: mismatched types ‘const std::valarray<_Tp>’ and ‘const char [12]’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95:0, from Main.cc:1: /usr/include/c++/7/valarray:1186:1: note: candidate: template std::_Expr, typename std::__fun::result_type> std::operator<(const std::valarray<_Tp>&, const _Tp&) _DEFINE_BINARY_OPERATOR(<, __less) ^ /usr/include/c++/7/valarray:1186:1: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::valarray<_Tp>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95:0, from Main.cc:1: /usr/include/c++/7/valarray:1186:1: note: candidate: template std::_Expr, typename std::__fun::result_type> std::operator<(const std::valarray<_Tp>&, const std::valarray<_Tp>&) _DEFINE_BINARY_OPERATOR(<, __less) ^ /usr/include/c++/7/valarray:1186:1: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::valarray<_Tp>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/valarray:592:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95, from Main.cc:1: /usr/include/c++/7/bits/valarray_after.h:416:5: note: candidate: template std::_Expr, typename std::__fun::result_type> std::operator<(const std::valarray&, const std::_Expr<_Dom1, typename _Dom1::value_type>&) _DEFINE_EXPR_BINARY_OPERATOR(<, __less) ^ /usr/include/c++/7/bits/valarray_after.h:416:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: mismatched types ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ and ‘const char [12]’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/valarray:592:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95, from Main.cc:1: /usr/include/c++/7/bits/valarray_after.h:416:5: note: candidate: template std::_Expr, typename std::__fun::result_type> std::operator<(const std::_Expr<_Dom1, typename _Dom1::value_type>&, const std::valarray&) _DEFINE_EXPR_BINARY_OPERATOR(<, __less) ^ /usr/include/c++/7/bits/valarray_after.h:416:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/valarray:592:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95, from Main.cc:1: /usr/include/c++/7/bits/valarray_after.h:416:5: note: candidate: template std::_Expr, typename std::__fun::result_type> std::operator<(const typename _Dom::value_type&, const std::_Expr<_Dom1, typename _Dom1::value_type>&) _DEFINE_EXPR_BINARY_OPERATOR(<, __less) ^ /usr/include/c++/7/bits/valarray_after.h:416:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: mismatched types ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ and ‘const char [12]’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/valarray:592:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95, from Main.cc:1: /usr/include/c++/7/bits/valarray_after.h:416:5: note: candidate: template std::_Expr, typename std::__fun::result_type> std::operator<(const std::_Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&) _DEFINE_EXPR_BINARY_OPERATOR(<, __less) ^ /usr/include/c++/7/bits/valarray_after.h:416:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/valarray:592:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:95, from Main.cc:1: /usr/include/c++/7/bits/valarray_after.h:416:5: note: candidate: template std::_Expr, typename std::__fun::result_type> std::operator<(const std::_Expr<_Dom1, typename _Dom1::value_type>&, const std::_Expr<_Dom2, typename _Dom2::value_type>&) _DEFINE_EXPR_BINARY_OPERATOR(<, __less) ^ /usr/include/c++/7/bits/valarray_after.h:416:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/stack:61:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:89, from Main.cc:1: /usr/include/c++/7/bits/stl_stack.h:311:5: note: candidate: template bool std::operator<(const std::stack<_Tp, _Seq>&, const std::stack<_Tp, _Seq>&) operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) ^~~~~~~~ /usr/include/c++/7/bits/stl_stack.h:311:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::stack<_Tp, _Seq>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/set:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:87, from Main.cc:1: /usr/include/c++/7/bits/stl_multiset.h:913:5: note: candidate: template bool std::operator<(const std::multiset<_Key, _Compare, _Alloc>&, const std::multiset<_Key, _Compare, _Alloc>&) operator<(const multiset<_Key, _Compare, _Alloc>& __x, ^~~~~~~~ /usr/include/c++/7/bits/stl_multiset.h:913:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::multiset<_Key, _Compare, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/set:61:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:87, from Main.cc:1: /usr/include/c++/7/bits/stl_set.h:930:5: note: candidate: template bool std::operator<(const std::set<_Key, _Compare, _Alloc>&, const std::set<_Key, _Compare, _Alloc>&) operator<(const set<_Key, _Compare, _Alloc>& __x, ^~~~~~~~ /usr/include/c++/7/bits/stl_set.h:930:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::set<_Key, _Compare, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/queue:64:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:86, from Main.cc:1: /usr/include/c++/7/bits/stl_queue.h:336:5: note: candidate: template bool std::operator<(const std::queue<_Tp, _Seq>&, const std::queue<_Tp, _Seq>&) operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y) ^~~~~~~~ /usr/include/c++/7/bits/stl_queue.h:336:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::queue<_Tp, _Seq>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/vector:64:0, from /usr/include/c++/7/queue:61, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:86, from Main.cc:1: /usr/include/c++/7/bits/stl_vector.h:1618:5: note: candidate: template bool std::operator<(const std::vector<_Tp, _Alloc>&, const std::vector<_Tp, _Alloc>&) operator<(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y) ^~~~~~~~ /usr/include/c++/7/bits/stl_vector.h:1618:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::vector<_Tp, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/memory:81:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:82, from Main.cc:1: /usr/include/c++/7/bits/shared_ptr.h:416:5: note: candidate: template bool std::operator<(std::nullptr_t, const std::shared_ptr<_Tp>&) operator<(nullptr_t, const shared_ptr<_Tp>& __a) noexcept ^~~~~~~~ /usr/include/c++/7/bits/shared_ptr.h:416:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: mismatched types ‘const std::shared_ptr<_Tp>’ and ‘const char [12]’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/memory:81:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:82, from Main.cc:1: /usr/include/c++/7/bits/shared_ptr.h:408:5: note: candidate: template bool std::operator<(const std::shared_ptr<_Tp>&, std::nullptr_t) operator<(const shared_ptr<_Tp>& __a, nullptr_t) noexcept ^~~~~~~~ /usr/include/c++/7/bits/shared_ptr.h:408:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::shared_ptr<_Tp>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/memory:81:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:82, from Main.cc:1: /usr/include/c++/7/bits/shared_ptr.h:398:5: note: candidate: template bool std::operator<(const std::shared_ptr<_Tp>&, const std::shared_ptr<_Up>&) operator<(const shared_ptr<_Tp>& __a, const shared_ptr<_Up>& __b) noexcept ^~~~~~~~ /usr/include/c++/7/bits/shared_ptr.h:398:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::shared_ptr<_Tp>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/bits/shared_ptr.h:52:0, from /usr/include/c++/7/memory:81, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:82, from Main.cc:1: /usr/include/c++/7/bits/shared_ptr_base.h:1460:5: note: candidate: template bool std::operator<(std::nullptr_t, const std::__shared_ptr<_Tp, _Lp>&) operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept ^~~~~~~~ /usr/include/c++/7/bits/shared_ptr_base.h:1460:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: mismatched types ‘const std::__shared_ptr<_Tp, _Lp>’ and ‘const char [12]’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/bits/shared_ptr.h:52:0, from /usr/include/c++/7/memory:81, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:82, from Main.cc:1: /usr/include/c++/7/bits/shared_ptr_base.h:1452:5: note: candidate: template bool std::operator<(const std::__shared_ptr<_Tp, _Lp>&, std::nullptr_t) operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept ^~~~~~~~ /usr/include/c++/7/bits/shared_ptr_base.h:1452:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::__shared_ptr<_Tp, _Lp>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/bits/shared_ptr.h:52:0, from /usr/include/c++/7/memory:81, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:82, from Main.cc:1: /usr/include/c++/7/bits/shared_ptr_base.h:1441:5: note: candidate: template bool std::operator<(const std::__shared_ptr<_Tp1, _Lp>&, const std::__shared_ptr<_Tp2, _Lp>&) operator<(const __shared_ptr<_Tp, _Lp>& __a, ^~~~~~~~ /usr/include/c++/7/bits/shared_ptr_base.h:1441:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::__shared_ptr<_Tp1, _Lp>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/map:62:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:81, from Main.cc:1: /usr/include/c++/7/bits/stl_multimap.h:1076:5: note: candidate: template bool std::operator<(const std::multimap<_Key, _Tp, _Compare, _Alloc>&, const std::multimap<_Key, _Tp, _Compare, _Alloc>&) operator<(const multimap<_Key, _Tp, _Compare, _Alloc>& __x, ^~~~~~~~ /usr/include/c++/7/bits/stl_multimap.h:1076:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::multimap<_Key, _Tp, _Compare, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/map:61:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:81, from Main.cc:1: /usr/include/c++/7/bits/stl_map.h:1411:5: note: candidate: template bool std::operator<(const std::map<_Key, _Tp, _Compare, _Alloc>&, const std::map<_Key, _Tp, _Compare, _Alloc>&) operator<(const map<_Key, _Tp, _Compare, _Alloc>& __x, ^~~~~~~~ /usr/include/c++/7/bits/stl_map.h:1411:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::map<_Key, _Tp, _Compare, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/map:60:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:81, from Main.cc:1: /usr/include/c++/7/bits/stl_tree.h:1543:5: note: candidate: template bool std::operator<(const std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>&, const std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>&) operator<(const _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>& __x, ^~~~~~~~ /usr/include/c++/7/bits/stl_tree.h:1543:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/list:63:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:79, from Main.cc:1: /usr/include/c++/7/bits/stl_list.h:1918:5: note: candidate: template bool std::operator<(const std::__cxx11::list<_Tp, _Alloc>&, const std::__cxx11::list<_Tp, _Alloc>&) operator<(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) ^~~~~~~~ /usr/include/c++/7/bits/stl_list.h:1918:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::__cxx11::list<_Tp, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/bits/locale_conv.h:41:0, from /usr/include/c++/7/locale:43, from /usr/include/c++/7/iomanip:43, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:72, from Main.cc:1: /usr/include/c++/7/bits/unique_ptr.h:730:5: note: candidate: template bool std::operator<(std::nullptr_t, const std::unique_ptr<_Tp, _Dp>&) operator<(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) ^~~~~~~~ /usr/include/c++/7/bits/unique_ptr.h:730:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: mismatched types ‘const std::unique_ptr<_Tp, _Dp>’ and ‘const char [12]’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/bits/locale_conv.h:41:0, from /usr/include/c++/7/locale:43, from /usr/include/c++/7/iomanip:43, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:72, from Main.cc:1: /usr/include/c++/7/bits/unique_ptr.h:724:5: note: candidate: template bool std::operator<(const std::unique_ptr<_Tp, _Dp>&, std::nullptr_t) operator<(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) ^~~~~~~~ /usr/include/c++/7/bits/unique_ptr.h:724:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::unique_ptr<_Tp, _Dp>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/bits/locale_conv.h:41:0, from /usr/include/c++/7/locale:43, from /usr/include/c++/7/iomanip:43, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:72, from Main.cc:1: /usr/include/c++/7/bits/unique_ptr.h:713:5: note: candidate: template bool std::operator<(const std::unique_ptr<_Tp, _Dp>&, const std::unique_ptr<_Up, _Ep>&) operator<(const unique_ptr<_Tp, _Dp>& __x, ^~~~~~~~ /usr/include/c++/7/bits/unique_ptr.h:713:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::unique_ptr<_Tp, _Dp>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/functional:54:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:71, from Main.cc:1: /usr/include/c++/7/tuple:1410:5: note: candidate: template constexpr bool std::operator<(const std::tuple<_Tps ...>&, const std::tuple<_Elements ...>&) operator<(const tuple<_TElements...>& __t, ^~~~~~~~ /usr/include/c++/7/tuple:1410:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::tuple<_Tps ...>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/tuple:39:0, from /usr/include/c++/7/functional:54, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:71, from Main.cc:1: /usr/include/c++/7/array:262:5: note: candidate: template bool std::operator<(const std::array<_Tp, _Nm>&, const std::array<_Tp, _Nm>&) operator<(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b) ^~~~~~~~ /usr/include/c++/7/array:262:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::array<_Tp, _Nm>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/deque:64:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:68, from Main.cc:1: /usr/include/c++/7/bits/stl_deque.h:2276:5: note: candidate: template bool std::operator<(const std::deque<_Tp, _Alloc>&, const std::deque<_Tp, _Alloc>&) operator<(const deque<_Tp, _Alloc>& __x, ^~~~~~~~ /usr/include/c++/7/bits/stl_deque.h:2276:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::deque<_Tp, _Alloc>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/deque:64:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:68, from Main.cc:1: /usr/include/c++/7/bits/stl_deque.h:301:5: note: candidate: template bool std::operator<(const std::_Deque_iterator<_Tp, _Ref, _Ptr>&, const std::_Deque_iterator<_Tp, _RefR, _PtrR>&) operator<(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x, ^~~~~~~~ /usr/include/c++/7/bits/stl_deque.h:301:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::_Deque_iterator<_Tp, _Ref, _Ptr>’ cout<"Impossible!"; ^~~~~~~~~~~~~ In file included from /usr/include/c++/7/deque:64:0, from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:68, from Main.cc:1: /usr/include/c++/7/bits/stl_deque.h:293:5: note: candidate: template bool std::operator<(const std::_Deque_iterator<_Tp, _Ref, _Ptr>&, const std::_Deque_iterator<_Tp, _Ref, _Ptr>&) operator<(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x, ^~~~~~~~ /usr/include/c++/7/bits/stl_deque.h:293:5: note: template argument deduction/substitution failed: Main.cc:32:9: note: ‘std::ostream {aka std::basic_ostream}’ is not derived from ‘const std::_Deque_iterator<_Tp, _Ref, _Ptr>’