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 <iostream>
using namespace std;

int main()
{
	int n;
	string intro,str;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> intro >> str;
		for (int j = intro.length() - 1; j >= 0; j--) {
			switch (intro[j])
			{
			case 'A': {
				string res;
				res.reserve(str.length());
				for (int k = str.length() - 1; k >= 0; k--) {
					res.push_back(str[k]);
				}
				str = res;
			}
				break;
			case 'C': {
				string res;
				res.reserve(str.length());
				for (int k = 0; k < str.length(); k++) {
					res.push_back(str[(k + 1) % str.length()]);
				}
				str = res;
			}
					  break;
			case 'E': {
				string res;
				res.reserve(str.length());
				for (int k = 0; k < str.length(); k++) {
					if (k < str.length() / 2) {
						res.push_back(str[k + str.length() - str.length() / 2]);
					}
					else if (k >= str.length() - str.length() / 2) {
						res.push_back(str[k - (str.length() - str.length() / 2)]);
					}
					else {
						res.push_back(str[k]);
					}
				}
				str = res;
			}
					  break;
			case 'J': {
				string res;
				res.reserve(str.length());
				for (int k = 0; k < str.length(); k++) {
					res.push_back(str[(k + str.length() - 1) % str.length()]);
				}
				str = res;
			}
				break;
			case 'M': {
				for (int k = 0;k < str.length(); k++) {
					if (str[k] <= '9' && str[k] >= '0') {
						str[k] = '0' + (str[k] - '0' + 1) % 10;
					}
				}
			}
				break;
			case 'P': {
				for (int k = 0; k < str.length(); k++) {
					if (str[k] <= '9' && str[k] >= '0') {
						str[k] = '0' + (str[k] - '0' + 9) % 10;
					}
				}
			}
				break;
			}
		}
		cout << str << endl;
	}
	return 0;
}

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

int main() {
  int n; cin >> n;
  while(n--) {
    string member; cin >> member;
    string s; cin >> s;
    int siz = s.size();
    for(int i = member.size()-1; i >= 0; i--) {
      char c = member[i];
      if(c == 'C') {;
        s = s.substr(1, siz) + s[0];
      } else if(c == 'J') {
        s = s[siz-1] + s.substr(0, siz-1);
      } else if(c == 'E') {
        string temp = s.substr(0, siz/2 + siz%2);
        s = s.substr(siz/2, siz) + temp;
      } else if(c == 'A') {
        reverse(s.begin(), s.end());
      } else if(c == 'M') {
        for(int j = 0; j < siz; j++) {
          if('0' <= s[j] && s[j] <= '9') {
            if(s[j] != '9') s[j]++;
            else s[j] = '0';
          }
        }
      } else if(c == 'P') {
        for(int j = 0; j < siz; j++) {
          if('0' <= s[j] && s[j] <= '9') {
            if(s[j] != '0') s[j]--;
            else s[j] = '9';
          }
        }
      }
    }
    cout << s << endl;
  }
}

C++: #include "bits/stdc++.h"
#define pb push_back
#define mt make_tuple
#define all(a) (a).begin(),(a).end()
#define frep(i,a,n) for(int i=(a);i<(n);++i)
#define rep(i, n) for(int i=0;i<(n);++i)
#define rrep(i, n) for(int i=n-1;i>=0;--i)
#define debug(x) cout << #x << " : " << x << " ------------ " << endl;
using namespace std;
int main()
{
    int n;
    cin >> n;
    while (n--) {
        string o;
        cin >> o;
        string m;
        cin >> m;
        
        rrep (i, o.length()) {
            switch (o[i]) {
                case 'A':
                    reverse(all(m));
                    break;
                case 'J':
                    rotate(m.rbegin(), m.rbegin() + 1, m.rend());
                    break;
                case 'C':
                    rotate(m.begin(), m.begin() + 1, m.end());
                    break;
                case 'P': {
                    auto it = m.begin();
                    while (it != m.end()) {
                        if (isdigit(*it) && --(*it) < '0') *it = '9';
                        ++it;
                    }
                    break; }
                case 'M': {
                    auto it = m.begin();
                    while (it != m.end()) {
                        if (isdigit(*it) && ++(*it) > '9') *it = '0';
                        ++it;
                    }
                    break; }
                case 'E': {
                    int len = m.length();
                    string f = m.substr(0, len / 2);
                    char mdl = m.length() % 2 ? m[len / 2] : 0;
                    string b = m.substr((len + 1) / 2);
                    m = b + mdl + f;
                    break; }
                default:
                    break;
            }
        }
        cout << m << endl;
    }
    return EXIT_SUCCESS;
}