text: #ifndef SCREEN_H_
  #define SCREEN_H_
  
  #include "stddef.h"
  
  /*
   * screen_init:
   *  Initializes the terminal.
   *
   */
  
  void screen_init(void);
  
  /*
   * screen_write:
   *  Writes the given buffer @buf of length @len on the screen, automatically
   *  advancing the cursor and scrolling the screen if necessary.
   *
   * @param buf - The buffer containing the data to be displayed
   * @param len - Length of the buffer.
   * @return    - The number of written bytes
   *
   */
  
  size_t screen_write(char *buf, size_t len);
  
  /*
   * screen_delete:
   *  Deletes the current character and updates the position of the cursor.
   *
   */
  
  void screen_delete(void);
  
  /*
   * screen_delete_line:
   *  Deletes current line and updates the position of the cursor. The cursor
   *  will be placed at the beginning of the current line after this routine
   *  ends.
   *
   */
  
  void screen_delete_line(void);
  
  #endif
  