Go: // Keitai Message
// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=2006&lang=jp
package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var table = []string{
	"",
	".,!? ",
	"abc",
	"def",
	"ghi",
	"jkl",
	"mno",
	"pqrs",
	"tuv",
	"wxyz",
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n := nextInt(sc)

	for i := 0; i < n; i++ {
		message := nextString(sc)
		currentButton, count := 0, 0
		for _, word := range message {
			// 確定の処理を書く
			if word == '0' {
				if currentButton == 0 {
					count = 0
					continue
				}
				mod := len(table[currentButton])
				tmp := table[currentButton][(count-1)%mod]
				currentButton, count = 0, 0
				fmt.Printf("%c", tmp)
			} else {
				count++
				currentButton = int(word) - 48 // '0'はASCIIで48
			}
		}
		fmt.Println()
	}
}

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, err := strconv.Atoi(sc.Text())
	if err != nil {
		panic(err)
	}
	return i
}

func nextString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<cctype>
#include<complex>
#include<iostream>
#include<sstream>
#include<algorithm>
#include<functional>
#include<vector>
#include<string>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<bitset>
using namespace std;
const int dx[] = {1,0,-1,0},dy[] = {0,1,0,-1};
#define INF 1e+8
#define EPS 1e-8
#define rep(i,j) for(int i = 0; i < (j); i++)
#define reps(i,j,k) for(int i = j; i < k; i++)
typedef long long ll;
typedef pair<int,int> Pii;
int main(){
	int n;
	cin >> n;
	string change[] = {"",".,!? ","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};	
	while(n--){
		string str;
		cin >> str;
		int len = str.size();
		string ans = "";
		rep(i,len){
			if(str[i] == '0')continue;
			int sub = i;
			while(str[i] == str[++sub]);
			ans += change[str[sub-1]-48][(sub-i-1)%change[str[sub-1]-48].size()];
			i = sub;
		}
		
		cout << ans << endl;
	}
	
	return 0;
}

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

// ?????¬???????????¬??????
#pragma region MACRO
#define P(x) cout << (x) << endl
#define p(x) cout << (x)
#define PED cout << "\n"
#define rep(i,n) for(int i=0; i<(int)n; ++i)
#define REP(i,x,n) for(int i=x; i<(int)n; ++i)
#define repi(i,n) for(int i=0; i<=(int)n; ++i)
#define REPI(i,x,n) for(int i=x; i<=(int)n; ++i)
#define ILP while(true)
#define FOR(i,c) for(__typeof((c).begin())!=(c).begin(); i!=(c).end(); ++i)
#define ALL(c) (c).begin(), (c).end()
#define mp make_pair
#pragma endregion

// ???
#pragma region TYPE_DEF
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<string, string> pss;
typedef pair<string, int> psi;
typedef pair<int, string> pis;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long double> vld;
typedef vector<long> vl;
typedef vector<long long> vll;
typedef vector<string> vs;
#pragma endregion

// Effective std
#pragma region ESTD
template<typename C, typename T> int count(C& c, T t) { return count(ALL(c), t); }
template<typename C, typename F> int count_if(C& c, F f) { return count_if(ALL(c), f); }
template<typename C, typename T> void erase(C& c, T t) { remove(ALL(c), t), c.end(); }
template<typename C> void remove(vector<C>& c, unsigned int index) { c.erase(c.begin()+index); }
template<typename C, typename T, typename U> void replace(C& c, T t, U u) { replace(ALL(c), t, u); }
template<typename C, typename F, typename U> void replace_if(C& c, F f, U u) { (ALL(c), f, u); }
template<typename C> void reverse(C& c) { reverse(ALL(c)); }
template<typename C> void sort(C& c) { sort(ALL(c)); }
template<typename C, typename Pred> void sort(C& c, Pred p) { sort(ALL(c), p); }
#pragma endregion

// ?????°
#pragma region CONST_VAL
constexpr int PI = (2*acos(0.0));
constexpr int EPS = (1e-9);
constexpr int MOD = (int)(1e9+7);
constexpr int INF = 100000000;
#pragma endregion

#define int long long

vector<vector<char> > buttons = {
    {'.',',','!','?'},
    {'a','b','c'},
    {'d','e','f'},
    {'g','h','i'},
    {'j','k','l'},
    {'m','n','o'},
    {'p','q','r','s'},
    {'t','u','v'},
    {'w','x','y','z'}
};

signed main()
{
    int n;
    cin >> n;
    while(n--) {
        string s;
        cin >> s;
        string ans = "";
        int bt = 0;
        int cnt = 0;
        for(int i=0; i<s.size(); ++i) {
            int num = s[i] - '0';
            if(num==0) {
                if(bt==0) continue;
                if(bt==1||bt==7||bt==9) {
                    cnt %= 4;
                    if(cnt==0) cnt = 3;
                    else cnt--;
                }
                else {
                    cnt %= 3;
                    if(cnt==0) cnt = 2;
                    else cnt--;
                }
                ans += buttons[bt-1][cnt];
                bt = 0;
                cnt = 0;
                continue;
            }
            if(bt!=num) {
                bt = num;
                cnt = 1;
            }
            else cnt++;
        }
        cout << ans << endl;
    }
    return 0;
}

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

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int n;
	cin >> n;

	vector<string> assign(10);
	assign[1] = ".,!? ";
	assign[2] = "abc";
	assign[3] = "def";
	assign[4] = "ghi";
	assign[5] = "jkl";
	assign[6] = "mno";
	assign[7] = "pqrs";
	assign[8] = "tuv";
	assign[9] = "wxyz";
	
	for(int i = 0; i < n; ++i) {
		string input, output;
		cin >> input;

		int cnt = 0;
		string candidate = "";
		for(int j = 0; j < (int)input.size(); ++j) {
			if(input[j] == '0') {
				output += candidate;
				candidate = "";
				cnt = 0;
			}
			else {
				const string& str = assign[input[j] - '0'];
				candidate = str[cnt];
				cnt = (cnt + 1) % str.size();
			}
		}

		cout << output << endl;
	}

	return EXIT_SUCCESS;
}

C++: #include<stdio.h>
#include<string.h>
main(){
    int N;
    char S[1025];
    scanf("%d",&N);
    char str[][6] = {".,!? ","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
    for(int i = 0;i < N;i++){
        scanf("%s",S);
        int num = 0;//?????¨??\??????????????????
        int count = 0;
        for(int j = 0;j < strlen(S);j++){
            if(S[j] != '0'){num = S[j] - '0';}
            if(S[j] == '0' && num == 0){continue;}
            if(S[j] == S[j+1]){
                count++;
                continue;
            }
            printf("%c",str[num-1][count%(strlen(str[num-1]))]);
            count = 0;
            num = 0;
        }
        printf("\n");
    }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <cstdlib>

using std::cin;
using std::cout;
using std::endl;

char keitai[][6] =
{
	".,!? ",	
	"abc",
	"def",
	"ghi",
	"jkl",
	"mno",
	"pqrs",
	"tuv",
	"wxyz"
};

char out_keitai(int num, int count) {
	if (num == 1) {
		if (count%5 != 0) {
			return keitai[num-1][(count%5)-1];
		}else {
			return keitai[num-1][4];
		}
	}else if (num == 7 || num == 9) {
		if (count%4 != 0) {
			return keitai[num-1][(count%4)-1];
		}else {
			return keitai[num-1][3];
		}
	}else {
		if (count%3 != 0) {
			return keitai[num-1][(count%3)-1];
		}else {
			return keitai[num-1][2];
		}
	}
}
int main(void) {
	int n;
	char inp;
	std::string str;

	getline(cin, str);
	n = atoi(str.c_str());

	for (int i = 0; i < n; i++) {
		getline(cin, str);
		int num;
		int count = 0;
		for (int j = 0; j < str.length(); j++) {
			std::string dstr;
			dstr = str.substr(j,1);
			num = atoi(dstr.c_str());
			if (num != 0) {
				count++;
				int seq = 1;
				int next_num;
				while (seq) {
					dstr = str.substr(j+1,1);
					next_num = atoi(dstr.c_str());
					if (num == next_num) {
						count++;
						j++;
					}else {
						seq = 0;
						cout << out_keitai(num,count);
						count = 0;
					}
				}	
			}
		}
		cout << endl;
	}
	return 0;
}