(require 'cc-mode)
(require 'compile-my)

(add-hook   'c-mode-hook #'enable-line-mode)
(add-hook 'c++-mode-hook #'enable-line-mode)

(defun c-or-cpp-switch-to-body-or-header-file ()
  (interactive)
  (let*((suffixes      (if (eq major-mode 'c-mode) '("c"  "h") '("cc" "hh")))
        (file-suffix   (nth 0 suffixes))
        (header-suffix (nth 1 suffixes))
        (name          (buffer-name)) )
    (let ((is-body                (string= (file-name-extension name) file-suffix))
          (file-name-no-extension (file-name-sans-extension name)) )
      (find-file
       (format "%s/%s" default-directory
               (if is-body
                   (format "include/%s.%s" file-name-no-extension header-suffix)
                 (format "../%s.%s"      file-name-no-extension file-suffix) ))))))

(define-key c++-mode-map "\C-c\C-c" #'compile-with-prompt)
(define-key   c-mode-map "\C-c\C-c" #'compile)
(define-key   c-mode-map "\C-o;"    #'c-or-cpp-switch-to-body-or-header-file)
(define-key c++-mode-map "\C-o;"    #'c-or-cpp-switch-to-body-or-header-file)