Language: C++

#include <bits/stdc++.h>
int main(){
	int n;
	cin>>n;
	while(n--){
		string s,ss;
		cin>>s>>ss;
		for(int i=s.size()-1;i>=0;i--){
			if(s[i]=='P')
				for(int j=0;j<ss.size();j++)
					if(ss[j]>='0'&&ss[j]<='9')
						ss[j]=(ss[j]-'0'+9)%10+'0';
			if(s[i]=='M')
				for(int j=0;j<ss.size();j++)
					if(ss[j]>='0'&&ss[j]<='9')
						ss[j]=(ss[j]-'0'+1)%10+'0';
			if(s[i]=='A')reverse(ss.begin(),ss.end());
			if(s[i]=='P')for(int k=0;k<=ss.size()/2;k++)swap(ss[k],ss[k+(ss.size()+1)/2]);
			if(s[i]=='J')ss=ss[ss.size()-1]+ss.substr(0,s.size()-1);
			if(s[i]=='C')ss=ss.substr(1,s.size()-1)+s[0];
		}
		cout<<ss<<endl;
	}
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:9: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    4 |         cin>>n;
      |         ^~~
      |         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:6:17: error: 'string' was not declared in this scope
    6 |                 string s,ss;
      |                 ^~~~~~
a.cc:6:17: 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:
/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:7:22: error: 's' was not declared in this scope
    7 |                 cin>>s>>ss;
      |                      ^
a.cc:7:25: error: 'ss' was not declared in this scope
    7 |                 cin>>s>>ss;
      |                         ^~
a.cc:17:38: error: 'reverse' was not declared in this scope; did you mean 'std::reverse'?
   17 |                         if(s[i]=='A')reverse(ss.begin(),ss.end());
      |                                      ^~~~~~~
      |                                      std::reverse
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:249:1: note: 'std::reverse' declared here
  249 | reverse(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last);
      | ^~~~~~~
a.cc:18:69: error: 'swap' was not declared in this scope
   18 |                         if(s[i]=='P')for(int k=0;k<=ss.size()/2;k++)swap(ss[k],ss[k+(ss.size()+1)/2]);
      |                                                                     ^~~~
a.cc:18:69: note: suggested alternatives:
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181:
/usr/include/c++/14/bits/regex.h:2230:5: note:   'std::__cxx11::swap'
 2230 |     swap(match_results<_Bi_iter, _Alloc>& __lhs,
      |     ^~~~
In file included from /usr/include/c++/14/bits/stl_pair.h:61,
                 from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60:
/usr/include/c++/14/bits/move.h:226:5: note:   'std::swap'
  226 |     swap(_Tp& __a, _Tp& __b)
      |     ^~~~
/usr/include/c++/14/bits/move.h:226:5: note:   'std::swap'
In file included from /usr/include/c++/14/exception:166,
                 from /usr/include/c++/14/stdexcept:38,
                 from /usr/include/c++/14/system_error:43,
                 from /usr/include/c++/14/bits/ios_base.h:46,
                 from /usr/include/c++/14/streambuf:43,
                 from /usr/include/c++/14/bits/streambuf_iterator.h:35,
                 from /usr/include/c++/14/iterator:66,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:54:
/usr/include/c++/14/bits/exception_ptr.h:229:5: note:   'std::__exception_ptr::swap'
  229 |     swap(exception_ptr& __lhs, exception_ptr& __rhs)
      |     ^~~~
In file included from /usr/include/c++/14/filesystem:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:200:
/usr/include/c++/14/bits/fs_path.h:736:15: note:   'std::filesystem::__cxx11::swap'
  736 |   inline void swap(path& __lhs, path& __rhs) noexcept { __lhs.swap(__rhs); }
      |               ^~~~
a.cc:22:17: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   22 |                 cout<<ss<<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:22:27: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   22 |                 cout<<ss<<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)
      |     ^~~~