Language: C++

#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<string>
typedef long long Int;
int main(){
  int d;
  cin>>d;
  if(d==25) cout<<"Christmas"<<endl;
  if(d==24) cout<<"Christmas Eve"<<endl;
  if(d==23) cout<<"Christmas Eve Eve"<<endl;
  if(d==22) cout<<"Christmas Eve Eve Eve"<<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    9 |   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:10:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 |   if(d==25) 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:10:32: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   10 |   if(d==25) cout<<"Christmas"<<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:11:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |   if(d==24) 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:11:36: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |   if(d==24) 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:12:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   12 |   if(d==23) 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:12:40: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   12 |   if(d==23) 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:13:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   13 |   if(d==22) 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:13:44: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   13 |   if(d==22) cout<<"Christmas Eve Eve Eve"<<endl;
      |                                            ^~~~
      |                                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~