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 <vector>
#include <iostream>
#include <utility>
#include <algorithm>
#include <string>
#include <deque>
#include <queue>
#include <tuple>
#include <queue>
#include <functional>
#include <cmath>
#include <iomanip>
#include <map>
#include <set>
#include <numeric>
#include <unordered_map>
#include <unordered_set>
#include <complex>
#include <iterator>
#include <array>
#include <memory>
#include <stack>
#define vi vector<int>
#define vvi vector<vector<int> >
#define ll long long int
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vb vector<bool>
#define vc vector<char>
#define vs vector<string>
#define ld long double
#define INF 1e9
#define EPS 0.0000000001
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define all(in) in.begin(), in.end()
template<class T, class S> void cmin(T &a, const S &b) { if (a > b)a = b; }
template<class T, class S> void cmax(T &a, const S &b) { if (a < b)a = b; }
#define MAX 9999999
using namespace std;
typedef pair<int, int> pii;
typedef pair<double,double>pdd;
typedef pair<ll,ll>pll;
string solve(string s,char order){
    if(order=='C'){
        char hoge=s[0];
        s.erase(s.begin());
        s.push_back(hoge); return s;
    }if(order=='J'){
        char hoge=s[s.size()-1];
        s.insert(s.begin(),hoge);
        s.erase(s.end()-1);
        return s;
    }if(order=='E'){
        
        string hoge;
        if(s.size()%2)hoge.push_back(s[(s.size()-1)/2]);
        for(int i=0; i<=(s.size()-1)/2;i++){
            if(i==(s.size()-1)/2&&s.size()%2)continue;
            hoge.push_back(s[i]);
        }
        string gotiusa;
        for(int i=(int)(s.size()-1)/2+1;i<s.size();i++)
            gotiusa.push_back(s[i]);
        return (gotiusa+hoge);
    }if(order=='A'){
        reverse(s.begin(),s.end());
        return s;
    }if(order=='P'){
        rep(i,s.size()){
            if('0'<=s[i]&&s[i]<='9'){
                if(s[i]=='0')s[i]='9';
                else{string hoge=to_string(s[i]-'1'); s[i]=hoge[0];}
            }
        }
        return s;
    }if(order=='M'){
        rep(i,s.size()){
            if('0'<=s[i]&&s[i]<='9'){
                if(s[i]=='9')s[i]='0';
                else{string hoge=to_string(s[i]-'0'+1); s[i]=hoge[0];}
            }
        }
        return s;
    }
    
    return s;
}
int main(){
    int gotiusa; cin>>gotiusa;
    rep(_,gotiusa){
        string key,s;
        cin>>key;
        cin>>s;
        for(int i=(int)key.size()-1; i>=0;i--){
            s=solve(s,key[i]);
        }
        cout<<s<<endl;
    }
}

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main(){
  int n,i,j,k,orderlen,strlen;
  string order,str,tempstr1,tempstr2;
  char temp;
  cin >> n;
  for(i=0;i<n;i++){
    cin >> order;
    reverse(order.begin(),order.end());
    cin >> str;
    orderlen=order.size();
    strlen=str.size();
    for(j=0;j<orderlen;j++){
      if(order[j]=='J'){
	temp=str[strlen-1];
	for(k=strlen-1;k>=1;k--){
	  str[k]=str[k-1];
	}
	str[0]=temp;
      }
      else if(order[j]=='C'){
	temp=str[0];
	for(k=0;k<strlen-1;k++){
	  str[k]=str[k+1];
	}
	str[strlen-1]=temp;
      }
      else if(order[j]=='E'){
	tempstr1=tempstr2="";
	for(k=0;k<strlen;k++){
	  if(k<strlen/2) tempstr1+=str[k];
	  else tempstr2+=str[k];
	}
	str="";
	str+=tempstr2;
	str+=tempstr1;
	if(strlen%2==1){
	  temp=str[0];
	  for(k=0;k<strlen/2;k++){
	    str[k]=str[k+1];
	  }
	  str[strlen/2]=temp;
	}
      }
      else if(order[j]=='A'){
	reverse(str.begin(),str.end());
      }
      else if(order[j]=='P'){
	for(k=0;k<strlen;k++){
	  if('1'<=str[k]&&str[k]<='9') str[k]-=1;
	  else if(str[k]=='0') str[k]='9';
	}
      }else{//M
	for(k=0;k<strlen;k++){
	  if('0'<=str[k]&&str[k]<='8') str[k]+=1;
	  else if(str[k]=='9') str[k]='0';
	}
      }
    }
    cout << str << endl;
  }
  return 0;
}