How to use a sub folder in default controller route in CodeIgniter 3 - 7-Views

While setting $route[‘default_controller’] without subdirectory it is working but I wanted to change it inside subdirectory and it’s not working.

Here is the solution to the issue.
Please create a file in the insideapplication/core directory. the file name would be MY_Router.php

paste the following content inside the file “MY_Router.php”, it will work like a charm.

<?php

class MY_Router extends CI_Router {
  protected function _set_default_controller() {

    if (empty($this->default_controller)) {

      show_error('Unable to determine what should be displayed. A default route has not been specified in the routing file.');
    }
    // Is the method being specified?
    if (sscanf($this->default_controller, '%[^/]/%s', $class, $method) !== 2) {
      $method = 'index';
    }

    // This is what I added, checks if the class is a directory
    if( is_dir(APPPATH.'controllers/'.$class) ) {

      // Set the class as the directory

      $this->set_directory($class);

      // $method is the class

      $class = $method;

      // Re check for slash if method has been set

      if (sscanf($method, '%[^/]/%s', $class, $method) !== 2) {
        $method = 'index';
      }
    }

    if ( ! file_exists(APPPATH.'controllers/'.$this->directory.ucfirst($class).'.php')) {

      // This will trigger 404 later

      return;
    }
    $this->set_class($class);
    $this->set_method($method);
    // Assign routed segments, index starting from 1
    $this->uri->rsegments = array(
      1 => $class,
      2 => $method
    );
    log_message('debug', 'No URI present. Default controller set.');
  }
}

read more