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;

#define REP(i,n) for(int i=0;i<(n);i++)
#define ALL(v) (v).begin(),(v).end()
#define int long long
typedef pair<int,int> P;

//-----------------------------------------------------------------------

void decode(string &s,char c)
{
    if(c=='J'){
	s=s[s.size()-1]+s.substr(0,s.size()-1);
    }
    else if(c=='C'){
	s=s.substr(1)+s[0];
    }
    else if(c=='E'){
	if(s.size()%2==0) s=s.substr(s.size()/2)+s.substr(0,s.size()/2);
	else s=s.substr(s.size()/2+1)+s[s.size()/2]+s.substr(0,s.size()/2);
    }
    else if(c=='A'){
	reverse(ALL(s));
    }
    else if(c=='P'){
	REP(i,s.size()){
	    if(s[i]=='0') s[i]='9';
	    if('1'<=s[i] && s[i]<='9') s[i]--;
	}
    }
    else{
	REP(i,s.size()){
	    if('0'<=s[i] && s[i]<='8') s[i]++;
	    if(s[i]=='9') s[i]='0';
	}
    }
}
    
signed main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n; cin>>n;
    REP(i,n){
	string s,msg;
	cin>>s>>msg;
	for(int i=s.size()-1;i>=0;i--){
	    decode(msg,s[i]);
	}
	cout<<msg<<endl;
    }

}

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

int main(){
    int n;
    cin >> n;

    for(int i=0; i<n; i++){
        string order, m;
        cin >> order >> m;
        int len = m.length();
        for(int j=order.length()-1; j>=0; j--){
            switch(order[j]){
            case 'J':
                m = m.substr(len-1,1) + m.substr(0,len-1);
                break;
            case 'C':
                m = m.substr(1, len-1) + m.substr(0,1);
                break;
            case 'E':
                if(len%2==0){
                    m = m.substr((len+1)/2, len/2)
                        + m.substr(0, len/2);
                }else{
                    m = m.substr((len+2)/2, (len-1)/2)
                        + m.substr(len/2, 1)
                        + m.substr(0, (len-1)/2);
                }
                break;
            case 'A':
                reverse(m.begin(), m.end());
                break;
            case 'P':
                for(int d=0; d<len; d++){
                    if(m[d] >= '1' && m[d] <= '9'){
                        m[d]--;
                    }else if(m[d] == '0'){
                        m[d] = '9';
                    }
                }
                break;       
            case 'M':
                for(int d=0; d<len; d++){
                    if(m[d] >= '0' && m[d] <= '8'){
                        m[d]++;
                    }else if(m[d] == '9'){
                        m[d] = '0';
                    }
                }
                break;
            }
        }
        cout << m << endl;
    }
    return 0;
}

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

using namespace std;

int main(void) {
  int n;
  cin >> n;

  for (int i = 0; i < n; i++) {
    string s, t;
    cin >> s >> t;
    reverse(s.begin(), s.end());

    int sz = s.size(), tz = t.size();
    for (int j = 0; j < sz; j++) {
      if (s[j] == 'C') {
        t = t.substr(1, tz - 1) + t[0];
      } else if (s[j] == 'J') {
        t = t[tz - 1] + t.substr(0, tz - 1);
      } else if (s[j] == 'E') {
        string a = t.substr(0, tz / 2), b = t.substr((tz + 1) / 2, tz / 2);
        if (tz & 1) t = t[tz / 2];
        else t = "";
        t = b + t + a;
      } else if (s[j] == 'A') {
        reverse(t.begin(), t.end());
      } else if (s[j] == 'M') {
        for (int k = 0; k < tz; k++) {
          if (!isdigit(t[k])) continue;
          t[k] = (t[k] - '0' + 1) % 10 + '0';
        }
      } else {
        for (int k = 0; k < tz; k++) {
          if (!isdigit(t[k])) continue;
          t[k] = (t[k] - '0' - 1 + 10) % 10 + '0';
        }
      }
    }

    cout << t << endl;
  }

  return 0;
}