运行 ID: 31196

Main.cc:1:1: error: ‘de’ does not name a type
 de
 ^~
In file included from /usr/include/c++/7/cmath:43:0,
                 from Main.cc:4:
/usr/include/c++/7/ext/type_traits.h:162:35: error: ‘bool __gnu_cxx::__is_null_pointer’ redeclared as different kind of symbol
   __is_null_pointer(std::nullptr_t)
                                   ^
/usr/include/c++/7/ext/type_traits.h:157:5: note: previous declaration ‘template bool __gnu_cxx::__is_null_pointer(_Type)’
     __is_null_pointer(_Type)
     ^~~~~~~~~~~~~~~~~
/usr/include/c++/7/ext/type_traits.h:162:26: error: ‘nullptr_t’ is not a member of ‘std’
   __is_null_pointer(std::nullptr_t)
                          ^~~~~~~~~
Main.cc: In function ‘int main()’:
Main.cc:11:5: error: ‘cin’ was not declared in this scope
     cin>>x>>n;
     ^~~
Main.cc:11:5: note: suggested alternative: ‘sin’
     cin>>x>>n;
     ^~~
     sin