1. Basic Concepts of The User Interface
KwangWoo Choi
Department of Physics
Kangwon National University
 User Interface: Front-end of the software
For the easy way to access the software, the easy-to-use user
interface is necessary.
 CUI and GUI
- CUI(Character User Interface): User interface based on the keyboard
input. Ex. MS-DOS, Unix shell.
- GUI(Graphic User Interface): User interface based on the graphical
items such as icons, menus, toolbars, etc.
Ex. MS Windows, Unix X Window.
More intuitive than the CUI and easy to use.

2. Popular GUI Operating Systems
MS Windows 2000
X Window on Unix

3. Library for GUI  Basic elements of GUI
- Menu: Classified set of the commands
- Toolbar: Direct shortcut to the commands or menu items
- Dialog box: Interface for the interactive operation with users
 Example of the library for GUI
- Motif: Based on the X Window in Unix.
Supported by the cygwin in the MS Windows
Because it is written by C, the library is simple.
- Gtk: Based on the X Window in Unix.
Supported by the cygwin or Visual C++ in the MS Windows
Object oriented library, but written by C.
Recently, it is most popular GUI library and powerful.

4. Summary
 GUI is the intuitive user interface and easy to use for users.
 MS Windows and X Window are popular GUI operating systems.
The library for the user interface is developed on these operating
systems.
The library is developed that supports the basic elements of the
GUI such as menu, toolbar, and dialog box.