What is the role of region code in Cohen Sutherland Line clipping algorithm? code example

Example: Cohen Sutherland Line Clipping Algorithm: In the algorithm, first of all, it is detected whether line lies inside the screen or it is outside the screen. All lines come under any one of the following categories: Visible Not Visible Clipping Case

Cohen Sutherland Line Clipping Algorithm:
In the algorithm, first of all, it is detected whether line lies inside the screen or it is outside the screen. All lines come under any one of the following categories:

Visible
Not Visible
Clipping Case