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<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<queue>
#include<stack>
#include<map>
#include<set>

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
typedef pair<pii,int> piii;
typedef pair<ll,ll> pll;

#define reps(i,f,n) for(int i = int(f); i <= int(n); i++)
#define rep(i,n) reps(i,0,int(n)-1)
#define rrep(i,n) for(int i = n-1; i >= 0; i--)

#define all(x) (x).begin(),(x).end()
#define X first
#define Y second

#define sz size()
#define eb emplace_back

char str[12][6] ={"",".,!? ","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
int mod[12] = {0,5,3,3,3,3,3,4,3,4};

int main(void){
  int n;
  cin >> n;
  rep(test,n){
    string s;
    cin >> s;
    int num = -1;
    int cnt = -1;
    rep(i,s.sz){
      if(s[i] == '0'){
        if(num != -1){
          printf("%c", str[num][cnt%mod[num]]);
          num = -1;
          cnt = -1;
        }
      }else{
        num = s[i] - '0';
        cnt++;
      }
    }
    puts("");
  }
  return 0;
}

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

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define each(x, y) for (auto &x : y)
#define all(a) (a).begin(), (a).end()
#define bit(b) (1ll << (b))

using namespace std;

using i32 = int;
using i64 = long long;
using u64 = unsigned long long;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;
using vu64 = vector<u64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << '\n'; exit(0); }
inline void no() { cout << "No" << '\n'; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { return a / gcd(a, b) * b; }
inline u64 xorshift() { static u64 x = 88172645463325252ull; x = x ^ (x << 7); return x = x ^ (x >> 9); }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> inline void amax(T &x, T y) { if (x < y) x = y; }
template <typename T> inline void amin(T &x, T y) { if (x > y) x = y; }
template <typename T> inline T power(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { each(x, v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }
template <typename T, typename S> istream& operator>>(istream &is, pair<T, S> &p) { is >> p.first >> p.second; return is; }
template <typename T, typename S> ostream& operator<<(ostream &os, pair<T, S> &p) { os << p.first << ' ' << p.second; return os; }

void solve() {
  int n; cin >> n;
  rep(i, n) {
    string s; cin >> s;
    int n = s.size();

    string ans = "";
    vstr memo = {
      ".,!? ",
      "abc",
      "def",
      "ghi",
      "jkl",
      "mno",
      "pqrs",
      "tuv",
      "wxyz",
    };
    int prev = -1, x = -1;
    rep(i, n) {
      if (s[i] == '0') {
        if (x != -1) ans += memo[prev][x];
        x = -1, prev = -1;
      } else {
        int y = s[i] - '1';
        prev = y, x++;
        if (x >= memo[prev].size()) x = 0;
      }
    }
    cout << ans << '\n';
  }
}

C++: #include <iostream>

using namespace std;

int    nextInt()    { int d;      cin >> d;   return d;   }
string nextString() { string str; cin >> str; return str; }

string solve(string input) {
  string ret;

  char keys[][5] = {
    {},
    {'.', ',', '!', '?', ' '},
    {'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'}
  };
  
  int key_size[] = {
    -1, 5, 3, 3, 3, 3, 3, 4, 3, 4
  };
  
  char next;
  int idx = 0;
  for (int i = 0; i < input.size(); i++) {
    char c = input[i];
    if (c == '0') {
      ret += next;
      next = '\0';
      idx = 0;
    } else {
      next = keys[c - '0'][idx];
      idx = (idx + 1) % key_size[c - '0'];
    }
  }
  
  return ret;
}

int main() {
  int n = nextInt();
  for (int i = 0; i < n; i++) {
    string input = nextString();
    cout << solve(input) << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<cmath>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<cstring>

using namespace std;

#define INF 999999999

int main(){
	int N, i, j, pr, b, n, no[10]={1,5,3,3,3,3,3,4,3,4};
	string s;
	vector<string> c(10);
	c[0] = "a";
	c[1] = ".,!? ";
	c[2] = "abc";
	c[3] = "def";
	c[4] = "ghi";
	c[5] = "jkl";
	c[6] = "mno";
	c[7] = "pqrs";
	c[8] = "tuv";
	c[9] = "wxyz";
	
	cin >> N;
	for(i=0;i<N;i++){
		cin >> s;
		pr = 0;
		n = 0;
		//cout << s.size();
		for(j=0;j<s.size();j++){
			b = s[j] - '0';
			//cout << b;
			if(pr == b){
				n++;
			}
			else if(b==0){
				//cout << pr << n%no[pr] << endl;
				cout << c[pr][n%no[pr]];
			}
			else {
				n=0;
			}
			pr = b;
		}
		cout << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
	char a[9][5]={{'.',',','!','?',' '},{'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'}};
	int n,b=0,c=0,d=0;
	string s;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>s;b=d=c=0;
		char ss[100];
			for(int j=0;j<s.size();j++){
				if(s[j]=='0'&&c>0){
					if(s[j-1]=='1')d=(c-1)%5;
					else if(s[j-1]=='6'||s[j-1]=='8')d=(c-1)%4;
					else d=(c-1)%3;
					cout<<a[(int)(s[j-1]-'0')-1][d];
				c=0;
				}
				else c++;
				}
				cout<<endl;
	}
	return 0;
}

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

using namespace std;

int main(){
	int n; cin >> n;
	vector<string> button(10);
	button[1] = ".,!? ";
	button[2] = "abc";
	button[3] = "def";
	button[4] = "ghi";
	button[5] = "jkl";
	button[6] = "mno";
	button[7] = "pqrs";
	button[8] = "tuv";
	button[9] = "wxyz";
	for(int i = 0; i < n; ++i){
		string str; cin >> str;
		int acc = -1;
		int pre = 0;
		for(int j = 0; j < str.size(); ++j){
			if(str[j] == '0'){
				if(pre == 0) continue;
				int s = button[pre].size();
				char out = button[pre][acc % s];
				cout << out;
				acc = -1;
			}
			else{
				if(acc == -1){
					acc = 0;
					pre = str[j] - '0';
				}
				else{
					acc ++;
				}
			}

		}
		cout << endl;
	}
	return 0;
}