Move the cursor to coordinates (y,x), get a character from the
    terminal screen, and echo it on the specified window. The mvgetch
    function acts on the stdscr window.
    Format
      #include  <curses.h>
      int mvgetch  (int y, int x);
      int mvwgetch  (WINDOW *win, int y, int x);
1 – Arguments
 win
    A pointer to the window.
 y
    A window coordinate.
 x
    A window coordinate.
2 – Description
    The mvgetch and mvwgetch functions refresh the specified window
    before fetching the character.
3 – Return Values
    x                  The returned character.
    ERR                Indicates that the function causes the screen
                       to scroll illegally. For more information, see
                       the scrollok function in this section.