Emacs/ Elisp - Switch between buffer types. Example switch between only c++ *.cpp (c++-mode), files, c-mode *.c, c-mode *.h and so on.

swithc-buffer-major-mode-types.el

;;  Question: Is there a package/lisp code that lets me cycle through filetype buffers? 
;;  Reddit tpic: https://www.reddit.com/r/emacs/comments/5tjgsb/is_there_a_packagelisp_code_that_lets_me_cycle/
;;
;;
(require 'helm) ;;
(require 'cl)   ;;   

(defun switch-buffer-type (buffer-major-mode file-extension)
  (let ((items   (mapcar
                  (lambda (buf) (cons (buffer-name buf) buf))
                  (remove-if-not (lambda (buf)
                                     (and ;; if buffer-major-mode is nil - select buffer by file extension 
                                      (if buffer-major-mode
                                          (equal buffer-major-mode (buffer-local-value 'major-mode buf))
                                        t
                                        )
                                        ;; if file-extension is null - select buffer by major-mode
                                      (if file-extension
                                          (string-suffix-p file-extension (buffer-file-name buf))
                                        t
                                        )))
                                   (buffer-list)))))
  (helm
     :prompt "Buffer switch: "
     :sources  `((
                  (name       . "Dir: ")                                 
                  (candidates . ,items)
                  (action     . switch-to-buffer)
                  ))))) 

(defun switch-cpp-files ()
  (interactive)
  (switch-buffer-type 'c++-mode ".cpp"))

(defun switch-h-files ()
  (interactive)
  (switch-buffer-type 'c-mode ".h"))