View Compilation Error

0_0_39710180_3765.cpp: In function 'int main()':
0_0_39710180_3765.cpp:15:1: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
   15 | cin>>n;
      | ^~~
      | std::cin
In file included from 0_0_39710180_3765.cpp:1:
gcc-13.1.0/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
0_0_39710180_3765.cpp:17:11: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   17 | cin>>str>>endl;
      |           ^~~~
      |           std::endl
In file included from gcc-13.1.0/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/iostream:41:
gcc-13.1.0/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/ostream:735:5: note: 'std::endl' declared here
  735 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
0_0_39710180_3765.cpp:20:34: error: expected ')' before ';' token
   20 | reversetString(str,str.length()-1;
      |               ~                  ^
      |                                  )