Move the cursor to coordinates (y,x) and insert the character
    ch into the specified window. The mvinsch function acts on the
    stdscr window.

    Format

      #include  <curses.h>

      int mvinsch  (int y, int x, char ch);

      int mvwinsch  (WINDOW *win, int y, int x, char ch);

1 - Arguments

 win

    A pointer to the window.

 y

    A window coordinate.

 x

    A window coordinate.

 ch

    The character to be inserted at the window's coordinates.

2 - Description

    After the character is inserted, each character on the line
    shifts to the right, and the last character on the line is
    deleted.

3 - Return Values

    OK                 Indicates success.
    ERR                Indicates that the function makes the screen
                       scroll illegally. For more information, see
                       the scrollok function in this section.