Language: C++

#include <bits/stdc++.h>
usinng namespace std;
int main(){
  int n;
  cin>>n;
 if(n<2){cout<<1<<endl;}
else if (n<4){cout<<2<<endl;}
  else if (n<8){cout<<4<<endl;}
  else if (n<16){cout<<8<<endl;}
  else if (n<32){cout<<16<<endl;}
  else if (n<64){cout<<32<<endl;}
  else if (n<=100){cout<<64<<endl;}
}

Compiler output:
a.cc:2:1: error: 'usinng' does not name a type
    2 | usinng namespace std;
      | ^~~~~~
a.cc: In function 'int main()':
a.cc:5:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |   cin>>n;
      |   ^~~
      |   std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146,
                 from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:6:10: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    6 |  if(n<2){cout<<1<<endl;}
      |          ^~~~
      |          std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:6:19: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    6 |  if(n<2){cout<<1<<endl;}
      |                   ^~~~
      |                   std::endl
In file included from /usr/include/c++/14/istream:41,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:7:15: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    7 | else if (n<4){cout<<2<<endl;}
      |               ^~~~
      |               std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:7:24: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    7 | else if (n<4){cout<<2<<endl;}
      |                        ^~~~
      |                        std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:8:17: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    8 |   else if (n<8){cout<<4<<endl;}
      |                 ^~~~
      |                 std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:8:26: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    8 |   else if (n<8){cout<<4<<endl;}
      |                          ^~~~
      |                          std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:9:18: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    9 |   else if (n<16){cout<<8<<endl;}
      |                  ^~~~
      |                  std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:9:27: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    9 |   else if (n<16){cout<<8<<endl;}
      |                           ^~~~
      |                           std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:10:18: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 |   else if (n<32){cout<<16<<endl;}
      |                  ^~~~
      |                  std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:10:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   10 |   else if (n<32){cout<<16<<endl;}
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:11:18: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |   else if (n<64){cout<<32<<endl;}
      |                  ^~~~
      |                  std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:11:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |   else if (n<64){cout<<32<<endl;}
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:12:20: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   12 |   else if (n<=100){cout<<64<<endl;}
      |                    ^~~~
      |                    std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:12:30: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   12 |   else if (n<=100){cout<<64<<endl;}
      |                              ^~~~
      |                              std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~