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 <algorithm>
#include <iostream>
#include <limits.h>
#include <math.h>
#include <set>
#include <stack>
#include <stdlib.h>
#include <string>
#include <vector>

#define el endl
#define fd fixed
#define INF INT_MAX/2-1
#define pb push_back

using namespace std;

string num = "0123456789";

string mrj(string s) {
  return s[s.length()-1] + s.substr(0, s.length()-1);
}

string missc(string s) {
  return s.substr(1, s.length()-1) + s[0];
}

string mre(string s) {
  if (s.length() | 2) return s.substr(s.length()/2+1, s.length()/2) + s[s.length()/2] + s.substr(0, s.length()/2);
  else return s.substr(s.length()/2, s.length()/2) + s.substr(0, s.length()/2);
}

string mra(string s) {
  string res = "";
  for (int i = s.length()-1; i >= 0; i--) {
    res += s[i];
  }
  return res;
}

string drp(string s) {
  for (int i = 0; i < s.length(); i++) {
    int index = (int)num.find(s[i]);
    if (index > 0) {
      s[i] = num[(index+9)%10];
    }
  }
  return s;
}

string mrm(string s) {
  for (int i = 0; i < s.length(); i++) {
    int index = (int)num.find(s[i]);
    if (index > 0) {
      s[i] = num[(index+1)%10];
    }
  }
  return s;
}

int main() {
  int n;
  string order, message;
  cin >> n;
  while (n--) {
    cin >> order >> message;
    for (int i = order.length()-1; i >= 0; i--) {
      if (order[i] == 'J') message = mrj(message);
      if (order[i] == 'C') message = missc(message);
      if (order[i] == 'E') message = mre(message);
      if (order[i] == 'A') message = mra(message);
      if (order[i] == 'P') message = drp(message);
      if (order[i] == 'M') message = mrm(message);
    }
    cout << message << el;
  }
}

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

int main() {
  int T;
  cin >> T;
  while(T--) {
    string s,t;
    cin >> t >> s;
    int n=s.size();
    for(int j=t.size()-1; j>=0; j--) {
      if(t[j]=='C') rotate(s.begin(),s.begin()+1,s.end());
      if(t[j]=='J') rotate(s.begin(),s.end()-1,s.end());
      if(t[j]=='E') {
        if(s.size()%2) s=s.substr(n/2+1)+s[n/2]+s.substr(0,n/2);
        else s=s.substr(n/2)+s.substr(0,n/2);
      }
      if(t[j]=='A') reverse(s.begin(),s.end());
      if(t[j]=='M') {
        for(int i=0; i<n; i++) {
          if(!isdigit(s[i])) continue;
          if(s[i]=='9') s[i]='0';
          else s[i]++;
        }
      }
      if(t[j]=='P') {
        for(int i=0; i<n; i++) {
          if(!isdigit(s[i])) continue;
          if(s[i]=='0') s[i]='9';
          else s[i]--;
        }
      }
    }
    cout << s << endl;
  }
  return 0;
}

C++: #include<deque>
#include<list>
#include<map>
#include<queue>
#include<set>
#include<stack>
#include<vector>
#include<algorithm>
#include<string>
#include<iostream>
#include<sstream>
#include<cmath>
#include<cstring>
using namespace std;
int main(){
  int i,j,k;
  int n;
  cin>>n;
  for(i=0;i<n;++i){
    char s[7],t[26];
    cin>>s>>t;
    int sln=strlen(s);
    int tln=strlen(t);
    for(j=sln-1;j>=0;--j){
      if(0){
      }else if(s[j]=='J'){
	char u=t[tln-1];
	for(k=tln-1;k>0;--k)
	  t[k]=t[k-1];
	t[0]=u;
      }else if(s[j]=='C'){
	char u=t[0];
	for(k=1;k<tln;++k)
	  t[k-1]=t[k];
	t[tln-1]=u;
      }else if(s[j]=='E'){
	char u[12];
	memcpy(u,t,tln/2*sizeof(char));
	memcpy(t,t+(tln+1)/2,tln/2*sizeof(char));
	memcpy(t+(tln+1)/2,u,tln/2*sizeof(char));
      }else if(s[j]=='A'){
	char u[26];
	for(k=0;k<tln;++k)
	  u[k]=t[tln-k-1];
	memcpy(t,u,tln*sizeof(char));
      }else if(s[j]=='P'){
	for(k=0;k<tln;++k){
	  if(0){
	  }else if(t[k]=='0'){
	    t[k]='9';
	  }else if('1'<=t[k]&&t[k]<='9'){
	    --t[k];
	  }
	}
      }else if(s[j]=='M'){
	for(k=0;k<tln;++k){
	  if(0){
	  }else if(t[k]=='9'){
	    t[k]='0';
	  }else if('0'<=t[k]&&t[k]<='8'){
	    ++t[k];
	  }
	}
      }
    }
    cout<<t<<endl;
  }
  return 0;
}