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>
#include <algorithm>
#include <vector>
#include <string>
#include <cstdio>
#include <cstring>
using namespace std;

#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define DEB 0
#define all(x) x.begin(), x.end()

int main(){
  int n;
  string order, mess, tmp;
  cin>>n;
  while(n--){
    cin >> order >> mess;
    for(int i=order.size()-1; i>=0; i--){
      switch(order[i]){
      case 'C':
	mess = mess.substr(1) + mess.substr(0,1);
	break;
      case 'J':
	mess = mess.substr(mess.size()-1) + mess.substr(0,mess.size()-1);
	break;
      case 'E':
	if( mess.size()%2==0 ){
	  mess = mess.substr(mess.size()/2) + mess.substr(0,mess.size()/2);
	}else{
	  mess = mess.substr(mess.size()/2+1) + mess[mess.size()/2] + mess.substr(0,mess.size()/2);
	}
	break;
      case 'A':
	reverse(all(mess));
	break;
      case 'P':
	rep(j,mess.size()){
	  if( '0'<=mess[j] && mess[j]<='9' ){
	    if( mess[j]=='0' ){
	      mess[j] = '9';
	    }else{
	      mess[j]--;
	    }
	  }
	}
	break;
      case 'M':
	rep(j,mess.size()){
	  if( '0'<=mess[j] && mess[j]<='9' ){
	    if( mess[j]=='9' ){
	      mess[j] = '0';
	    }else{
	      mess[j]++;
	    }
	  }
	}
	break;
      }
#if DEB
      cout << ":: " << mess << endl;
#endif
    }
    cout << mess << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,k,n) for(int i = (k); i < (n); i++)
#define REP(i,n) FOR(i,0,n)
#define INF 114514810
#define MOD 1000000007
#define ALL(a) (a).begin(),(a).end()
#define pb(x) push_back(x)
#define ms(m,v) memset(m,v,sizeof(m))
#define D10  fixed<<setprecision(10) 
typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int, int> P;
typedef long long ll;
struct edge{ int from, to, cost; };

string s, mes;
string solve(string s, char c)
{
	if (c == 'J') return s.substr(1) + s[0];
	if (c == 'C') return s[s.size() - 1] + s.substr(0, s.size() - 2);
	if (c == 'E')
	{
		if (s.size() % 2 == 0) return s.substr(s.size() / 2, s.size() - 1) + s.substr(0, s.size()/2);
		else return s.substr(s.size() / 2 + 1, s.size()) + s[s.size() / 2] + s.substr(0, s.size() / 2);
	}
	if (c == 'A')
	{
		string r = "";
		REP(i, s.size()) r += s[s.size() - i - 1];
		return r;
	}
	if (c == 'P')
	{
		string r = "";
		REP(i, s.size())
		{
			if (isdigit(s[i]))
			{
				if (s[i] == '9') r += '0';
				else r += s[i] + 1;
			}
			else r += s[i];
		}
	}
	if (c == 'M')
	{
		string r = "";
		REP(i, s.size())
		{
			if (isdigit(s[i]))
			{
				if (s[i] == '0') r += '9';
				else r += s[i] - 1;
			}
			else
			{
				r += s[i];
			}
		}
	}
}
int main()
{
	int n;
	cin >> n;

	REP(i, n)
	{
		cin >> mes >> s;
		REP(i, mes.size())
		{
			s = solve(s, mes[i]);
		}
		cout << s << endl;
	}
}

C++: #include <bits/stdc++.h>
using namespace std;

int main(void) {

    int n; cin >> n;
    while (n--) {
        string psg, msg; cin >> psg >> msg;
        int len = msg.size();

        for (int i = psg.size()-1; i >= 0; i--) {
            switch (psg[i]) {
            case 'J':
                // right shift
                msg = string(1, msg[len-1]) + msg.substr(0, len-1);
                break;
            case 'C':
                // left shift
                msg = msg.substr(1, len-1) + string(1, msg[0]);
                break;
            case 'E':
                // swap
                if (len%2 == 0) {
                    string l = msg.substr(0, len/2);
                    string r = msg.substr(len/2, len/2);
                    msg = r+l;
                } else {
                    string l = msg.substr(0, len/2);
                    string r = msg.substr(len/2+1, len/2);
                    msg = r+msg[len/2]+l;
                }
                break;
            case 'A':
                // reverse
                reverse(msg.begin(), msg.end());
                break;
            case 'P':
                // decrement digits
                for (auto &m : msg) {
                    if (isdigit(m)) {
                        if (m == '0') m = '9';
                        else m--;
                    }
                }
                break;
            case 'M':
                // increment digits
                for (auto &m : msg) {
                    if (isdigit(m)) {
                        if (m == '9') m = '0';
                        else m++;
                    }
                }
                break;
            default:
                break;
            }
        }
        cout << msg << endl;
    }

    return 0;
}