The MVC pattern dynamic draw circle
4.0
(1) when a user in the graphical user interface when you enter the radius of a circle, the program will display the circumference and area of a circle, and draw the circle (2) when a user in the graphical user interface when dragging the ruler said the radius of the circle, it automatically displays the RADIUS, circumference and area of a circle and draw graphics in the graphical interface; (3) the assumptions required to extend such a feature: requirements in the program interface and displays it on the surface area of a sphere of RADIUS, analysis of how to implement this function, and implements this feature.