Language: C++

#include<bits/stdc++.h>

int main(){
  std::string s;
  cin >> s;
  if(s == "SAT"){
	cout << 1 << endl;
  } else if (s == "FRI"){
	cout << 2 << endl;
  } else if(s == "THU"){
	cour << 3 << endl;
  } else if(s == "WED"){
	cout << 4 << endl;
  } else if(s == "TUE"){
    cout << 5 << endl;
  } else if(s == "MON"){
    cout << 6 < endl;
  } else {
cout << 7 << endl;
  }

}

Compiler output:
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 >> s;
      |   ^~~
      |   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:7:9: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    7 |         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:7:22: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    7 |         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:9:9: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    9 |         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:9:22: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    9 |         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:11:9: error: 'cour' was not declared in this scope
   11 |         cour << 3 << endl;
      |         ^~~~
a.cc:11:22: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |         cour << 3 << endl;
      |                      ^~~~
      |                      std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:13:9: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   13 |         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:13:22: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   13 |         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:15:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   15 |     cout << 5 << 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:15:18: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   15 |     cout << 5 << endl;
      |                  ^~~~
      |                  std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:17:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   17 |     cout << 6 < 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:17:17: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   17 |     cout << 6 < endl;
      |                 ^~~~
      |                 std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:19:1: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   19 | cout << 7 << 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:19:14: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   19 | cout << 7 << endl;
      |              ^~~~
      |              std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~