Language: C++

#include<iostream>

using namespaces std ;

int main()
{
  int d;
  cin>>d;
  if(d==22)
  {
    cout<<"Christmas Eve Eve Eve"<<endl;
    return 0;
  }
  else if(d==23)
  {
    cout<<"Christmas Eve Eve"<<endl;
    return 0;
  }
  else if(d==24)
  {
    cout<<"Christmas Eve"<<endl;
    return 0;
  }
  else if(d==25)
  {
    cout<<"Christmas"<<endl;
    return 0;
  }
 return 0;
}

Compiler output:
a.cc:3:7: error: expected nested-name-specifier before 'namespaces'
    3 | using namespaces std ;
      |       ^~~~~~~~~~
a.cc: In function 'int main()':
a.cc:8:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    8 |   cin>>d;
      |   ^~~
      |   std::cin
In file included 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:11:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |     cout<<"Christmas Eve Eve Eve"<<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:11:36: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |     cout<<"Christmas Eve Eve Eve"<<endl;
      |                                    ^~~~
      |                                    std::endl
In file included from /usr/include/c++/14/iostream:41:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:16:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   16 |     cout<<"Christmas Eve Eve"<<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:16:32: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   16 |     cout<<"Christmas Eve Eve"<<endl;
      |                                ^~~~
      |                                std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:21:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   21 |     cout<<"Christmas Eve"<<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:21:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   21 |     cout<<"Christmas Eve"<<endl;
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:26:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   26 |     cout<<"Christmas"<<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:26:24: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   26 |     cout<<"Christmas"<<endl;
      |                        ^~~~
      |                        std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~