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 <string>

using namespace std;

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

    auto decryptJ = [](const string &s) {
        return s.back() + s.substr(0, s.size() - 1);
    };

    auto decryptC = [](const string &s) { return s.substr(1) + s.front(); };

    auto decryptE = [](const string &s) {
        if (s.size() % 2 == 0) {
            return s.substr(s.size() / 2) + s.substr(0, s.size() / 2);
        }
        else {
            return s.substr(s.size() / 2 + 1) + s[s.size() / 2] +
                   s.substr(0, s.size() / 2);
        }
    };

    auto decryptA = [](const string &s) {
        auto r = s;
        reverse(begin(r), end(r));
        return r;
    };

    auto decryptP = [](const string &s) {
        auto r = s;
        for (auto &&c : r) {
            if (c < '0' || '9' < c) {
                continue;
            }

            c = (c - '0' + 10 - 1) % 10 + '0';
        }
        return r;
    };

    auto decryptM = [](const string &s) {
        auto r = s;
        for (auto &&c : r) {
            if (c < '0' || '9' < c) {
                continue;
            }

            c = (c - '0' + 1) % 10 + '0';
        }
        return r;
    };

    for (int i = 0; i < n; ++i) {
        string order, message;
        cin >> order;
        cin >> message;
        reverse(begin(order), end(order));

        for (auto &&c : order) {
            switch (c) {
            case 'J':
                message = decryptJ(message);
                break;
            case 'C':
                message = decryptC(message);
                break;
            case 'E':
                message = decryptE(message);
                break;
            case 'A':
                message = decryptA(message);
                break;
            case 'P':
                message = decryptP(message);
                break;
            case 'M':
                message = decryptM(message);
                break;
            }
        }
        cout << message << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	while(n--){
		string s,ss;
		cin>>s>>ss;
		for(int i=s.size()-1;i>=0;i--){
			if(s[i]=='P')
				for(int j=0;j<ss.size();j++)
					if(ss[j]>='0'&&ss[j]<='9')
						ss[j]=(ss[j]-'0'+9)%10+'0';
			if(s[i]=='M')
				for(int j=0;j<ss.size();j++)
					if(ss[j]>='0'&&ss[j]<='9')
						ss[j]=(ss[j]-'0'+1)%10+'0';
			if(s[i]=='A')reverse(ss.begin(),ss.end());
			if(s[i]=='P')for(int k=0;k<=ss.size()/2;k++)swap(ss[k],ss[k+(ss.size()+1)/2]);
			if(s[i]=='J')ss=ss[ss.size()-1]+ss.substr(0,s.size()-1);
			if(s[i]=='C')ss=ss.substr(1,s.size()-1)+s[0];
		}
		cout<<ss<<endl;
	}
}

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

#define rep(i, n) for(int i = 0; i < n; i++)

typedef long long ll;
using namespace std;
int mod = 1000000007;

int main(void){
    //J -> 左回転
    //C -> 右回転
    //E -> 半分にして入れ替え
    //A -> 反転
    //P -> 数字をインクリメント
    //M -> 数字をデクリメント
    int N; cin >> N;
    vector<string> ans;
    rep(i, N){
        string order, recv;
        cin >> order >> recv;
        int lenS = recv.length();
        for(int j = order.length(); j >= 0; j--){
            string temp = "";
            switch(order[j]){
                case 'J':
                    temp += recv[lenS-1];
                    rep(k, lenS-1) temp += recv[k];
                    recv = temp;
                    break;
                case 'C':
                    for(int k = 1; k < lenS; k++) temp += recv[k];
                    temp += recv[0];
                    recv = temp;
                    break;
                case 'E':
                    if((lenS & 1) == 0){
                        for(int k = lenS/2; k < lenS; k++) temp += recv[k];
                        rep(k, lenS/2) temp += recv[k];
                        recv = temp; 
                    }
                    else{
                        for(int k = lenS/2+1; k < lenS; k++) temp += recv[k];
                        temp += recv[lenS/2];
                        rep(k, lenS/2) temp += recv[k];
                        recv = temp; 
                    }
                    break;
                case 'A':
                    reverse(recv.begin(), recv.end());
                    break;
                case 'P':
                    rep(k, recv.length()){
                        if('0' <= recv[k] && recv[k] <= '9'){
                            if(recv[k] == '0') recv[k] = '9';
                            else recv[k]--;
                        }
                    }
                    break;
                case 'M':
                    rep(k, recv.length()){
                        if('0' <= recv[k] && recv[k] <= '9'){
                            if(recv[k] == '9') recv[k] = '0';
                            else recv[k]++;
                        }
                    }
                    break; 
            }
        }
        ans.push_back(recv);
    }
    rep(i, ans.size()) cout << ans[i] << endl;
    return 0;
}