Loop breaking.

/*
 * Trying to refactor someone else's code from codingame website.
 * I am trying to replace a massive if else block with a switch statement.
 * I cannot figure out why my statement is not equivalent to there's.
 * Sorry for the long post. My Git seems broken lately.
 * Can someone explain please?
 */

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

#define SWITCH_

int L = 8;
int C = 8;
int N;

std::vector<std::string> rows = {
  {"########"},
  {"# @    #"},
  {"#     X#"},
  {"# XXX  #"},
  {"#   XX #"},
  {"#   XX #"},
  {"#     $#"},
  {"########"}
};

std::pair<int, int> move(std::string s, std::pair<int, int> lpos) {
  if      (s == "SOUTH") { lpos.second++; }
  else if (s == "WEST")  { lpos.first--; }
  else if (s == "EAST")  { lpos.first++; }
  else if (s == "NORTH") { lpos.second--; }
  return lpos;
}

bool isPassable(std::string dir, std::pair<int, int> pos, bool dis) {
  std::pair<int, int> npos = move(dir, pos);
  if (npos.first < 0 || npos.second < 0 || npos.first >= C || npos.second >= L) {
    return false;
  }
  auto c = rows[npos.second][npos.first];
  return !(c == '#' || (c == 'X' && !dis));
}

int main() {
  std::pair<int, int> pos;
  std::vector<std::string> directions = { "SOUTH", "EAST", "NORTH", "WEST" };
  std::vector<std::pair<int, int>> tl;
  std::string out = "";
  bool BM {};
  rows.resize(L);
  for (auto i = 0ul; i < L; i++) {
    auto f = rows[i].find("@");
    if (f != std::string::npos) {
      pos = std::make_pair(f, i);
    }
    for (auto j = 0ul; j < rows[i].size(); j++) {
      if (rows[i][j] == 'T') {
        tl.emplace_back(j, i);
      }
    }
  }

  std::string dir = "SOUTH";
  /* loop forever */ while (true) {
    if (!isPassable(dir, pos, BM)) {
      for (auto const & ds : directions) {
        if (isPassable(ds, pos, BM)) {
          dir = ds;
          break;
        }
      }
    }

    out += dir + "\n";
    pos = move(dir, pos);

    char block = rows[pos.second][pos.first];
#ifdef SWITCH_
    //My Way...Seems to loop infinitely.
    auto complete { false }; /* flag for loop termination - initially false */
    switch (block) {
      case 'X':
        rows[pos.second].replace(pos.first, 1, " ");
        break;

      case '$':
        /* loop should terminate - set flag */
        complete = true;
        break;

      default:
        for (auto const & ds : directions) {
          if (ds[0] == block) {
            dir = ds;
            break;
          }
        }
    }
    if (complete) { /* terminate forever loop */ break; }
#else
    //Their Way...Works
    if (block == 'X') {
      rows[pos.second].replace(pos.first, 1, " ");
    }
    else if (block == '$') {
      break;
    }
    else {
      for (auto const & ds : directions) {
        if (ds[0] == block) {
          dir = ds;
          /* terminate forever loop */  break;
        }
      }
    }
#endif

    // Loop check
    N++;
    if (N > C * L) {
      out = "LOOP\n";
      break;
    }
  }
  std::cout << out;
}