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 <vector>
#include <string>
#include <algorithm>
#define rep(i,a) for(int i = 0 ; i < a ; i ++)

using namespace std;

int main(void){
  int N;
  cin>>N;
  while(N--){
    string a,s;
    cin>>a>>s;
    reverse(a.begin(),a.end());
    rep(i,a.size()){
      switch(a[i]){
        case 'A':
          reverse(s.begin(),s.end());
          break;
        case 'J':
        case 'C':
          s=s.substr(1)+s[0];
          break;
          s=s.substr(1)+s.substr(0,1);
          break;
        case 'M':
          rep(i,s.size()){
            if('0'<=s[i]&&s[i]<='9'){
              if(s[i]=='9')s[i]='0';
              else s[i]++;
            }
          }
          break;
        case 'P':
          rep(i,s.size()){
            if('0'<=s[i]&&s[i]<='9'){
              if(s[i]=='0')s[i]='9';
              else s[i]--;
            }
          }
          break;
        case 'E':
          string res = "";
          for(int i = s.size()/2 ; i < s.size() ; i ++)res+=s[i];
          for(int i = 0 ; i < s.size()/2 ; i ++)res+=s[i];
          s = res;
          break;
      }
    }
      cout<<s<<endl;
    
  }
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <cctype>

using namespace std;

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

string revC(string s) {
  return s.substr(1) + s[0];
}

string revE(string s) {
  int n = s.size();
  string ret = s.substr(n-n/2);
  if(n % 2) ret += s[n/2];
  ret += s.substr(0, n/2);
  return ret;
}

string revA(string s) {
  reverse(s.begin(), s.end());
  return s;
}

string revP(string s) {
  for(int i=0; i<s.size(); i++)
    if(isdigit(s[i])) s[i] = static_cast<char>(((s[i]-'0') + 9) % 10 + '0');
  return s;
}

string revM(string s) {
  for(int i=0; i<s.size(); i++)
    if(isdigit(s[i])) s[i] = static_cast<char>(((s[i]-'0') + 11) % 10 + '0');
  return s;
}

int main() {
  int n;
  cin >> n;
  
  while(n--) {
    string cmd, s;
    cin >> cmd >> s;
    reverse(cmd.begin(), cmd.end());
    int Ncmd = cmd.size();
    for(int i=0; i<Ncmd; i++) {
      switch(cmd[i]) {
      case 'A': s = revA(s); break;
      case 'C': s = revC(s); break;
      case 'E': s = revE(s); break;
      case 'J': s = revJ(s); break;
      case 'M': s = revM(s); break;
      case 'P': s = revP(s); break;
      }
    }
    cout << s << endl;
  }
  
  return 0;
}

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

int main()
{
    int n, len;
    cin >> n;
    string msg, srv;
    while (cin >> srv >> msg, n--) {
        len = msg.size();
        for (int i = srv.size() - 1; i >= 0; --i) {
            if (srv[i] == 'J') {
                rotate(msg.begin(), msg.end() - 1, msg.end());
            } else if (srv[i] == 'C') {
                rotate(msg.begin(), msg.begin() + 1, msg.end());
            } else if (srv[i] == 'E') {
                if (len % 2)
                    msg = msg.substr(len / 2 + 1) + msg[len / 2] + msg.substr(0, len / 2);
                else
                    msg = msg.substr(len / 2) + msg.substr(0, len / 2);
            } else if (srv[i] == 'A') {
                reverse(msg.begin(), msg.end());
            } else if (srv[i] == 'P') {
                for (int j = 0; j < len; ++j) {
                    if (msg[j] >= '0' && msg[j] <= '9')
                        msg[j] = (msg[j] + '9') % ':';
                }
            } else {
                for (int j = 0; j < len; ++j) {
                    if (msg[j] >= '0' && msg[j] <= '9')
                        msg[j] = (msg[j] + 1) % '9';
                }
            }
        }
        cout << msg << endl;
    }
    return 0;
}

C++: #include <stdio.h>
#include <string.h>
int main() {
    int N,i,j,k,q;char T[30],c[9];scanf("%d",&N);while (N--) {
        scanf("%s%s",&c,&T);j=strlen(c),k=strlen(T)-1;
        while (j--) {
            if (c[j]=='P') {
                for (i=k;i>=0;i--) if (T[i]<='9') {T[i]--;if (T[i]==47) T[i]=57;}
            } else if (c[j]=='M') {
                for (i=k;i>=0;i--) if (T[i]<='9') {T[i]++;if (T[i]==58) T[i]=48;}
            } else if (c[j]=='E') {
                for (i=k,q=(k-1)/2;q>=0;i--,q--) T[i]+=T[q],T[q]=T[i]-T[q],T[i]-=T[q];
            } else if (c[j]=='A') {
                for (i=0,q=k;i<q;i++,q--) T[i]+=T[q],T[q]=T[i]-T[q],T[i]-=T[q];
            } else if (c[j]=='J') {
                c[8]=T[k];for (i=k;i>0;i--) T[i]=T[i-1];T[0]=c[8];
            } else {
                c[8]=T[0];for (i=0;i<k;i++) T[i]=T[i+1];T[k]=c[8];
            }
        }
        puts(T);
    }
}