运行 ID: 21073

Main.cc:4:5: error: cannot declare ‘::main’ to be a global variable
 int main{
     ^~~~
Main.cc:5:8: error: expected ‘}’ before ‘;’ token
  cin>>n;
        ^
Main.cc:5:5: error: invalid user-defined conversion from ‘std::basic_istream::__istream_type {aka std::basic_istream}’ to ‘int’ [-fpermissive]
  cin>>n;
  ~~~^~~
In file included from /usr/include/c++/7/ios:44:0,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from Main.cc:1:
/usr/include/c++/7/bits/basic_ios.h:117:16: note: candidate is: std::basic_ios<_CharT, _Traits>::operator bool() const [with _CharT = char; _Traits = std::char_traits] 
       explicit operator bool() const
                ^~~~~~~~
/usr/include/c++/7/bits/basic_ios.h:117:16: note:   return type ‘bool’ of explicit conversion function cannot be converted to ‘int’ with a qualification conversion
Main.cc:6:2: error: ‘n’ does not name a type
  n=d*=g/=2;
  ^
Main.cc:7:2: error: ‘cout’ does not name a type; did you mean ‘cosl’?
  cout<