https://qiita.com/pengincoalition/items/bb5c611004b7c135efb7#comment-7c880a1ed3c32e05d140

maze.cpp

#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <random>
#include <vector>

class Maze {
  int start_x,
      start_y;
  int last_x,
      last_y;
  const char WALL  = '+',
             ROAD  = ' ',
             START = 'S',
             END   = 'E';
  std::vector<std::vector<char>> map;
  std::random_device rnd;

  bool digable(int x, int y) {
    return (y - 2 > 0             && map[y - 2][x] == WALL)
        || (y + 2 < map.size()    && map[y + 2][x] == WALL)
        || (x - 2 > 0             && map[y][x - 2] == WALL)
        || (x + 2 < map[y].size() && map[y][x + 2] == WALL);
  }

  void dig_up(int x, int y) {
    if (y - 2 > 0 && map[y - 2][x] == WALL) {
      map[y - 1][x] = ROAD;
      dig(x, y - 2);
    }
  }

  void dig_down(int x, int y) {
    if (y + 2 < map.size() && map[y + 2][x] == WALL) {
      map[y + 1][x] = ROAD;
      dig(x, y + 2);
    }
  }

  void dig_left(int x, int y) {
    if (x - 2 > 0 && map[y][x - 2] == WALL) {
      map[y][x - 1] = ROAD;
      dig(x - 2, y);
    }
  }

  void dig_right(int x, int y) {
    if (x + 2 < map[y].size() && map[y][x + 2] == WALL) {
      map[y][x + 1] = ROAD;
      dig(x + 2, y);
    }
  }

  using digger = void (Maze::*)(int width, int height);

  void dig(int x, int y) {
    const digger digger[] = {
        &Maze::dig_up, &Maze::dig_down, &Maze::dig_left, &Maze::dig_right,
    };
    const int num_digger = sizeof(digger) / sizeof(digger[0]);

    last_x = x;
    last_y = y;
    map[y][x] = ROAD;
    while (digable(x, y)) {
      (this->*digger[rnd() % num_digger])(x, y);
    }
  }

  void fill_wall(int width, int height) {
    map.resize(height);
    for (int y = 0; y < map.size(); y++) {
      map[y].resize(width);
      for (int x = 0; x < map[y].size(); x++) {
        map[y][x] = WALL;
      }
    }
  }

public:

  void make(int width, int height) {
    start_x = (rnd() % ((width  - 1) / 2)) * 2 + 1;
    start_y = (rnd() % ((height - 1) / 2)) * 2 + 1;

    fill_wall(width, height);
    dig(start_x, start_y);

    map[start_y][start_x] = START;
    map[last_y][last_x] = END;
  }

  void print() {
    for (int y = 0; y < map.size(); y++) {
      for (int x = 0; x < map[y].size(); x++) {
        std::cout << map[y][x];
      }
      std::cout << "\n";
    }
  }
};

int main(int argc, char **args) {
  int width, height;

  if (argc < 3) {
    std::cout << "width? ";
    std::cin  >>  width;
    std::cout << "height? ";
    std::cin  >>  height;
  } else {
    width  = atoi(args[1]);
    height = atoi(args[2]);
  }

  Maze maze;
  maze.make(width | 1, height | 1);
  maze.print();

  return 0;
}