Language: C++

#include<bits/stdc++.h>
using namepsace std;
int main(){
  string s;
  cin>>s;
  int l=s.size(), count=0;
  for(int i=0;i<l/2;i++){
  if(s[i]!=s[l-i])
    count++;
  }
  cout<<count<<endl;
return 0;
}

Compiler output:
a.cc:2:7: error: expected nested-name-specifier before 'namepsace'
    2 | using namepsace std;
      |       ^~~~~~~~~
a.cc: In function 'int main()':
a.cc:4:3: error: 'string' was not declared in this scope
    4 |   string s;
      |   ^~~~~~
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;
      |   ^~~
      |   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:5:8: error: 's' was not declared in this scope
    5 |   cin>>s;
      |        ^
a.cc:9:5: error: 'count' was not declared in this scope; did you mean 'std::count'?
    9 |     count++;
      |     ^~~~~
      |     std::count
In file included from /usr/include/c++/14/algorithm:86,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:101:1: note: 'std::count' declared here
  101 | count(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
      | ^~~~~
a.cc:11:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |   cout<<count<<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:11:9: error: 'count' was not declared in this scope; did you mean 'std::count'?
   11 |   cout<<count<<endl;
      |         ^~~~~
      |         std::count
/usr/include/c++/14/pstl/glue_algorithm_defs.h:101:1: note: 'std::count' declared here
  101 | count(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
      | ^~~~~
a.cc:11:16: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |   cout<<count<<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)
      |     ^~~~