Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	n := io.NextInt()
	for i := 0; i < n; i++ {
		s, t := io.NextLine(), io.NextLine()
		io.Println(f(s, t))
	}
}

func f(s, t string) string {
	for i := len(s) - 1; i >= 0; i-- {
		switch s[i] {
		case 'C':
			t = strings.Join([]string{t[1:], string(t[0])}, "")
		case 'J':
			t = strings.Join([]string{string(t[len(t)-1]), t[:len(t)-1]}, "")
		case 'E':
			if len(t)%2 == 1 {
				t = strings.Join([]string{t[len(t)/2+1:], string(t[len(t)/2]), t[:len(t)/2]}, "")
			} else {
				t = strings.Join([]string{t[len(t)/2:], t[:len(t)/2]}, "")
			}
		case 'A':
			r := []rune(t)
			for i, n := 0, len(r); i < n/2; i++ {
				r[i], r[n-i-1] = r[n-i-1], r[i]
			}
			t = string(r)
		case 'M':
			r := []rune(t)
			for i := 0; i < len(r); i++ {
				if '0' <= r[i] && r[i] < '9' {
					r[i]++
				} else if r[i] == '9' {
					r[i] = '0'
				}
			}
			t = string(r)
		case 'P':
			r := []rune(t)
			for i := 0; i < len(r); i++ {
				if '0' < r[i] && r[i] <= '9' {
					r[i]--
				} else if r[i] == '0' {
					r[i] = '9'
				}
			}
			t = string(r)
		}
	}
	return t
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: #include <bits/stdc++.h>

using namespace std;

int main()
{
  string number = "0123456789";
  int n;
  cin >> n;
  while(n--){
    string order, message;
    cin >> order >> message;
    for(int i = order.size()-1; i >= 0; i--){
      if(order[i] == 'M'){
	for(int j = 0; j < message.size(); j++){
	  if('0' <= message[j] && message[j] <= '9'){
	    int idx = number.find(message[j]);
	    message[j] = number[(idx+1)%number.size()];
	  }
	}
      } else if(order[i] == 'P'){
    	for(int j = 0; j < message.size(); j++){
	  if('0' <= message[j] && message[j] <= '9'){
	    int idx = number.find(message[j]);
	    message[j] = number[(idx-1+number.size())%number.size()];
	  }
	}	
      } else if(order[i] == 'A'){
	reverse(message.begin(), message.end());
      } else if(order[i] == 'E'){
	for(int i = 0; i < message.size() / 2; i++){
	  swap(message[i], message[i + (message.size()+1) / 2]);
	}
      } else if(order[i] == 'C'){
	message = message.substr(1, message.size()-1) + message[0];
      } else if(order[i] == 'J'){
	message = message[message.size()-1] + message.substr(0, message.size()-1);
      }
    }
    cout << message << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <string>
#include <sstream>
#include <algorithm>
#include <vector>
#include <utility>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
 
using namespace std;
 
#define rep(i,n) for(int i=0; i<(n); i++)
#define repc(i,s,e) for(int i=(s); i<(e); i++)
#define pb(n) push_back((n))
#define mp(n,m) make_pair((n),(m))
#define all(r) r.begin(),r.end()
#define fi first
#define se second
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef vector<ll> vl;
typedef vector<vl> vll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
 
 
 
const int INF = 1000000;
const double EPS = 1e-8;
const int mod = 1e9 + 7;
 
string change(string s, char c){
	string ret;

	if(c == 'J'){
		ret += s[s.size() - 1];
		for(int i = 0; i < s.size() - 1; i++) ret += s[i];
	}else if(c == 'C'){
		for(int i = 1; i < s.size(); i++) ret += s[i];
		ret += s[0];
	}else if(c == 'E'){
		ret = s;
		for(int i = 0; i < s.size() / 2; i++){
			ret[i] = s[(s.size() - 1) / 2 + 1 + i];
			ret[(s.size() - 1) / 2 + 1 + i] = s[i];
		}
	}else if(c == 'A'){
		ret = s;
		reverse(all(ret));
	}else if(c == 'M'){
		ret = s;
		for(int i = 0; i < ret.size(); i++){
			if(ret[i] >= '0' && ret[i] < '9') ret[i]++;
			else if(ret[i] == '9') ret[i] = '0';
		}
	}else{
		ret = s;
		for(int i = 0; i < ret.size(); i++){
			if(ret[i] == '0') ret[i] = '9';
			else if(ret[i] > '0' && ret[i] <= '9') ret[i]--;
		}
	}

	return ret;
}


int main(){
	int n;
	cin>>n;
	string s, t;
	for(int i = 0; i < n; i++){
		cin>>s>>t;
		for(int i = 0; i < s.size(); i++){
			t = change(t, s[s.size() -1 -i]);
			//cout<<s[i]<<" "<<t<<endl;
		}
		cout<<t<<endl;
	}
}

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main()
{
    int n, len;
    cin >> n;
    string msg, srv;
    while (cin >> srv >> msg, n--) {
        len = msg.size();
        for (int i = srv.size() - 1; i >= 0; --i) {
            if (srv[i] == 'J') {
                rotate(msg.begin(), msg.end() - 1, msg.end());
            } else if (srv[i] == 'C') {
                rotate(msg.begin(), msg.begin() + 1, msg.end());
            } else if (srv[i] == 'E') {
                if (len % 2)
                    msg = msg.substr(len / 2 + 1) + msg[len / 2] + msg.substr(0, len / 2);
                else
                    msg = msg.substr(len / 2) + msg.substr(0, len / 2);
            } else if (srv[i] == 'A') {
                reverse(msg.begin(), msg.end());
            } else if (srv[i] == 'P') {
                for (int j = 0; j < len; ++j) {
                    if (msg[j] >= '0' && msg[j] <= '9')
                        msg[j] = (msg[j] - '0' + 9) % 10 + '0';
                }
            } else {
                for (int j = 0; j < len; ++j) {
                    if (msg[j] >= '0' && msg[j] <= '9')
                        msg[j] = (msg[j] - '0' + 1) % 10 + '0';
                }
            }
        }
        cout << msg << endl;
    }
    return 0;
}