Language: C++

#include<bits/stdc++.h>
using namespace tsd;
int main(){
  string S, T;
  cin >> S >> T;
  for(int i = 0; i < S.size(); i++){
    if(S.at(i) == T.at(i) && T.size() == S.size() + 1){
      cout << "Yes" << endl;
    } else {
      cout << "No" << endl;
    }
  }
}

Compiler output:
a.cc:2:17: error: 'tsd' is not a namespace-name
    2 | using namespace tsd;
      |                 ^~~
a.cc: In function 'int main()':
a.cc:4:3: error: 'string' was not declared in this scope
    4 |   string S, T;
      |   ^~~~~~
a.cc:4:3: note: suggested alternatives:
In file included from /usr/include/c++/14/string:41,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bits/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:5:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |   cin >> S >> T;
      |   ^~~
      |   std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:5:10: error: 'S' was not declared in this scope
    5 |   cin >> S >> T;
      |          ^
a.cc:5:15: error: 'T' was not declared in this scope
    5 |   cin >> S >> T;
      |               ^
a.cc:8:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    8 |       cout << "Yes" << 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:8:24: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    8 |       cout << "Yes" << 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:10:7: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 |       cout << "No" << 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:10:23: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   10 |       cout << "No" << endl;
      |                       ^~~~
      |                       std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~