Problem p01131 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <cmath>
#include <complex>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;

#define ll long long
#define vvi vector<vector<int>>
#define All(X) X.begin(), X.end()
#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define pb push_back
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

int main() {

  int m;
  cin >> m;
  REP(i, m) {
    string str;
    int num[5000] = {0};
    char now;
    int out = 0;
    char one[5] = {'.', ',', '!', '?', ' '};
    cin >> str;
    int hoge = str.size();
    REP(i, hoge) { num[i] = str[i] - '0'; };
    REP(c, hoge) {
      int k = 0;
      if (num[c] == 1) {
        while (num[c] == 1) {
          k++;
          c++;
        }
        out = (k + 4) % 5;
        cout << one[out];
      } else if (num[c] == 2) {
        while (num[c] == 2) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'a' + out;
        cout << now;
      } else if (num[c] == 3) {
        while (num[c] == 3) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'd' + out;
        cout << now;
      } else if (num[c] == 4) {
        while (num[c] == 4) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'g' + out;
        cout << now;
      } else if (num[c] == 5) {
        while (num[c] == 5) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'j' + out;
        cout << now;
      } else if (num[c] == 6) {
        while (num[c] == 6) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'm' + out;
        cout << now;
      } else if (num[c] == 7) {
        while (num[c] == 7) {
          k++;
          c++;
        }
        out = (k + 3) % 4;
        now = 'p' + out;
        cout << now;
      } else if (num[c] == 8) {
        while (num[c] == 8) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 't' + out;
        cout << now;
      } else if (num[c] == 9) {
        while (num[c] == 9) {
          k++;
          c++;
        }
        out = (k + 3) % 4;
        now = 'w' + out;
        cout << now;
      }
    }
    cout << endl;
  }
}


Error: 0

Fixed submission:

#include <algorithm>
#include <cmath>
#include <complex>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;

#define ll long long
#define vvi vector<vector<int>>
#define All(X) X.begin(), X.end()
#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define pb push_back
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

int main() {

  int m;
  cin >> m;
  REP(i, m) {
    string str;
    int num[1000] = {0};
    char now;
    int out = 0;
    char one[5] = {'.', ',', '!', '?', ' '};
    cin >> str;
    int hoge = str.size();
    REP(i, hoge) { num[i] = str[i] - '0'; };
    REP(c, hoge) {
      int k = 0;
      if (num[c] == 1) {
        while (num[c] == 1) {
          k++;
          c++;
        }
        out = (k + 4) % 5;
        cout << one[out];
      } else if (num[c] == 2) {
        while (num[c] == 2) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'a' + out;
        cout << now;
      } else if (num[c] == 3) {
        while (num[c] == 3) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'd' + out;
        cout << now;
      } else if (num[c] == 4) {
        while (num[c] == 4) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'g' + out;
        cout << now;
      } else if (num[c] == 5) {
        while (num[c] == 5) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'j' + out;
        cout << now;
      } else if (num[c] == 6) {
        while (num[c] == 6) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 'm' + out;
        cout << now;
      } else if (num[c] == 7) {
        while (num[c] == 7) {
          k++;
          c++;
        }
        out = (k + 3) % 4;
        now = 'p' + out;
        cout << now;
      } else if (num[c] == 8) {
        while (num[c] == 8) {
          k++;
          c++;
        }
        out = (k + 2) % 3;
        now = 't' + out;
        cout << now;
      } else if (num[c] == 9) {
        while (num[c] == 9) {
          k++;
          c++;
        }
        out = (k + 3) % 4;
        now = 'w' + out;
        cout << now;
      }
    }
    cout << endl;
  }
}