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<string>
#include<vector>
#include<cstdio>
using namespace std;
int main(){
  int n;
  string x;
  string st;
  cin >>n;
  for(int i=0;i<n;i++){
    cin >> x;
    cin >> st;
    for(int j=x.size()-1;j>=0;j--){
      if(x[j]=='C'){
	char stock;
	stock = st[0];
	st.erase(st.begin());
	st+=stock;
      }
      else if(x[j]=='J'){
	char stock;
	stock = st[st.size()-1];
	//	cout << "p1"<<endl;
	st.erase(st.size()-1);
	//cout <<"p2"<<endl;
	st.insert(st.begin(),stock);
      }
      else if(x[j]=='E'){
	string stock;
	int l=st.size()/2;
	for(int k=0;k<l;k++){
	  stock+=st[k];
	}
	string stock2;
	int od = st.size()%2;
	for(int k=l+od;k<l*2+od;k++){
	  stock2+=st[k];
	}
	char st3;
	if(od==1)st3+=st[l];
	st=stock2+st3+stock;
      }
      else if(x[j]=='A'){
	string stock;
	for(int k=0;st.empty()!=true;k++){
	  stock += st[0];
	  st.erase(st.begin());
	}
	//cout << stock <<endl;
	for(int k=stock.size()-1;k>=0;k--){
	  st+=stock[k];
	}
      }
      else if(x[j]=='M'){
	for(int k=0;k<st.size();k++){
	  if(st[k]>='0'&&st[k]<'9'){
	    st[k]++;
	  }
	  else if(st[k]=='9'){
	    st[k]='0';
	  }
	}
      }
      else if(x[j]=='P'){
	for(int k=0;k<st.size();k++){
	  if(st[k]>'0'&&st[k]<='9'){
	    st[k]--;
	  }
	  else if(st[k]=='0'){
	    st[k]='9';
	  }
	}
      }	

      //cout <<"it is "<<x[j]<<endl;
      //cout << st << endl;
    }
    cout << st << endl;
  }
  return 0;
}

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 = msg[len-1] + msg.substr(0, len-1);
                break;
            case 'C':
                // left shift
                msg = msg.substr(1, len-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 (n == '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;
}

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

using namespace std;

typedef long long LL;
typedef vector<int>    VI;
typedef vector<bool>   VB;
typedef vector<string> VS;

#define MP make_pair
#define PB push_back
#define ALL(x)  (x).begin(),(x).end()
#define rep(i, N)  for (int i = 0; i < (int)(N); i++)
#define REP(i, init, N)  for (int i = (init); i < (int)(N); i++)
#define DUMP( x ) cerr << #x << " = " << ( x ) << endl

int main(void) {
	int n;
	cin >> n;
	rep (i, n) {
		string order, msg;
		cin >> order >> msg;
		rep (j, order.size()) {
			switch (order[j]) {
				case 'J':
					msg = msg.substr(1) + msg[0];
					break;
				case 'C':
					msg = msg[msg.size() - 1] + msg.substr(0, msg.size() - 1);
					break;
				case 'E':
					if (msg.size() % 2) {
						string s1 = msg.substr(0, msg.size() / 2);
						string s2 = msg.substr(msg.size() / 2 + 1);
						msg = s2 + msg[msg.size() / 2] + s1;
					} else {
						string s1 = msg.substr(0, msg.size() / 2);
						string s2 = msg.substr(msg.size() / 2);
						msg = s2 + s1;
					}
					break;
				case 'A':
					reverse(ALL(msg));
					break;
				case 'P':
					for (char &c : msg) {
						if ('0' <= c && c <= '9') {
							c = (c == '9'? '0' : c + 1);
						}
					}
					break;
				case 'M':
					for (char &c : msg) {
						if ('0' <= c && c <= '9') {
							c = (c == '0'? '9' : c - 1);
						}
					}
					break;
				default:
					break;
			}
		}
		cout << msg << endl;
	}

    return 0;
}