Write a program that enables the user to add/remove points by clicking the left/right mouse button, and displays a noncrossed polygon that links all the points, as shown in Figure 22.11a. A polygon is crossed if two or more sides intersect, as shown in Figure 22.11b. Use the following algorithm to construct a polygon from a set of points.

Step 1: Given a set of points S, select the rightmost lowest point p₀ in the set S.Step 2: Sort the points in S angularly along the x-axis with p₀ as the center. If there is a tie and two points have the same angle, the one that is closer to p₀ is considered greater. The points in S are now sorted as p₀, p₁, p₂, ..., p_n-1.Step 3: The sorted points form a non-cross polygon.

INSTRUCTION Add: Left Click Remove: Right Click (a) (b) Crossed polygon