#include <iostream>

bool end_condition(char* buffer, const size_t maxbuflen, size_t nplaces, const char* chars, const size_t nchars) {

    if (nplaces < maxbuflen - 1) return false;
    for (size_t i = 0; i <= nplaces; i++) {
        if (buffer[i] != chars[nchars - 1]) return false;
    }
    return true;
}

bool round_done(size_t place, char* buffer, const char* chars, const size_t nchars) {
    if (place == 0) {
        return buffer[place] == chars[nchars - 1];
    }
    char temp = buffer[0];
    for (size_t i = 0; i <= place; i++) {
      if (buffer[i] != chars[nchars - 1]) return false;
    }
    return true;
}

int main() {
    const size_t maxbuflen = 3;
    const char* chars      = "abc";
    const size_t nchars    = 3;
    char buffer[maxbuflen + 1];
    bool end = false;

    /* "Zero out" the buffer */
    for (size_t i = 0; i <= maxbuflen; i++)
        buffer[i] = '\0';

    size_t nplaces = 0, curr_place = 0;
    while (!end) {
        for (size_t i = 0; i < nchars; i++) {
          buffer[curr_place] = chars[i];
          std::cout << buffer << std::endl;
          if (end_condition(buffer, maxbuflen, nplaces, chars, nchars)) end = true;
        }
        if (round_done(nplaces, buffer, chars, nchars)) {
            nplaces++;
            for (size_t i = 0; i <= nplaces; i++) {
              buffer[i] = chars[0];
            }
            curr_place++;
        }
        else {
            size_t temp = curr_place - 1;
            while (buffer[temp] == chars[nchars - 1] && temp != -1) {
              if (buffer[temp] != chars[nchars - 1]) break;
              temp--;
            }
            if (temp == -1) {
              buffer[curr_place - 1] = buffer[curr_place - 1] + 1;
              buffer[curr_place] = chars[0];
            }
            else {
              buffer[temp] = buffer[temp] + 1;
              temp++;
              while (temp <= curr_place) {
                buffer[temp] = chars[0];
                temp++;
              }
            }
        }
    }
    return 0;
}