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;

// region template
#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;

ll gcd(ll a, ll b) { return __gcd(a, b); }

ll euclid(ll a, ll b, ll &x, ll &y) {
    if (b) {
        ll d = euclid(b, a % b, y, x);
        return y -= a / b * x, d;
    }
    return x = 1, y = 0, a;
}

typedef unsigned long long ull;
typedef long double ld;
ull mod_mul(ull a, ull b, ull M) {
    ll ret = a * b - M * ull(ld(a) * ld(b) / ld(M));
    return ret + M * (ret < 0) - M * (ret >= (ll)M);
}
ull mod_pow(ull b, ull e, ull mod) {
    ull ans = 1;
    for (; e; b = mod_mul(b, b, mod), e /= 2)
        if (e & 1)
            ans = mod_mul(ans, b, mod);
    return ans;
}

const ll mod = 1000000007;
struct Mod {
    ll x;
    Mod(ll xx) : x(xx) {}
    Mod operator+(Mod b) { return Mod((x + b.x) % mod); }
    Mod operator-(Mod b) { return Mod((x - b.x) % mod); }
    Mod operator*(Mod b) { return Mod((x * b.x) % mod); }
    Mod operator/(Mod b) { return *this * invert(b); }
    Mod invert(Mod a) {
        ll x, y, g = euclid(a.x, mod, x, y);
        assert(g == 1);
        return Mod((x + mod) % mod);
    }
    Mod operator^(ll e) {
        if (!e)
            return Mod(1);
        Mod r = *this ^ (e / 2);
        r = r * r;
        return e & 1 ? *this * r : r;
    }
};
// endregion

int dp[11][156];

string unj(string s) {
    int n = s.length();
    return s.substr(n - 1) + s.substr(0, n - 1);
}

string unc(string s) {
    int n = s.length();
    return s.substr(1) + s.substr(0, 1);
}

string une(string s) {
    int n = s.length();
    if (s.size() & 1) {
        return s.substr(n / 2 + 1) + s.substr(n / 2, 1) + s.substr(0, n / 2);
    } else {
        return s.substr(n / 2) + s.substr(0, n / 2);
    }
}

string una(string s) {
    return string(s.rbegin(), s.rend());
}

string unp(string s) {
    for (char &c : s) if (isdigit(c)) c = '0' + (c - '0' + 9) % 10;
    return s;
}

string unm(string s) {
    for (char &c : s) if (isdigit(c)) c = '0' + (c - '0' + 1) % 10;
    return s;
}

int main() {
    cin.sync_with_stdio(0);
    cin.tie(0);
    cin.exceptions(cin.failbit);

    int n; cin >> n;
    rep(i, 0, n) {
        string ins, str; cin >> ins >> str;
        reverse(all(ins));
        for (char c : ins) {
            if (c == 'J') str = unj(str);
            if (c == 'C') str = unc(str);
            if (c == 'E') str = une(str);
            if (c == 'A') str = una(str);
            if (c == 'P') str = unp(str);
            if (c == 'M') str = unm(str);
        }
        cout << str << endl;
    }
}

C++: #include<iostream>
#include<stdlib.h>
using namespace std;
int main()
{
	int n;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		char messengers[7];
		char message[26];
		cin >> messengers;
		cin >> message;
		int messengersNum = strlen(messengers);
		int messLen = strlen(message);
		for (int j = 0; j < messengersNum; j++)
		{
			char c = messengers[j];
			if (c == 'J')
			{
				char tmp = message[0];
				for (int k = 0; k + 1 < messLen; k++)
				{
					message[k] = message[k + 1];
				}
				message[messLen - 1] = tmp;
			}
			else if (c == 'C')
			{
				char tmp = message[messLen - 1];
				for (int k = messLen - 1; k - 1 >= 0; k--)
				{
					message[k] = message[k - 1];
				}
				message[0] = tmp;
			}
			else if (c == 'E')
			{
				if (messLen % 2 == 0)
				{
					int range = messLen / 2;
					for (int k = 0; k + range< messLen; k++)
					{
						char tmp = message[k];
						message[k] = message[k + range];
						message[k + range] = tmp;
					}
				}
				else
				{
					int range = messLen / 2 + 1;
					for (int k = 0; k  + range < messLen; k++)
					{
						char tmp = message[k];
						message[k] = message[k + range];
						message[k + range] = tmp;
					}
				}
			}
			else if (c == 'A')
			{
				for (int k = 0; k < messLen - k; k++)
				{
					char tmp = message[k];
					message[k] = message[messLen - 1 - k];
					message[messLen - 1 - k] = tmp;
				}
			}
			else if (c == 'P')
			{
				for (int k = 0; k< messLen; k++)
				{
					if (message[k] >= '0' && message[k] <= '9')
					{
						message[k]++;
						if (message[k] > '9')
						{
							message[k] = '0';
						}
					}
				}
			}
			else if (c == 'M')
			{
				for (int k = 0; k< messLen; k++)
				{
					if (message[k] >= '0' && message[k] <= '9')
					{
						message[k]--;
						if (message[k] < '0')
						{
							message[k] = '9';
						}
					}
				}
			}
		}

		cout << message << endl;
	}
	return 0;
}