Check Whether a Point Lies Inside,Outside or On a Circle

This program checks whether a point (x,y) lies inside,outside or on a circle defined by 3 other points.

Syntax: iscircle(X,Y,x,y), where X=[x1 x2 x3] and Y=[y1 y2 y3]. Thus, a circle can be made out of these 3 points-->(x1,y1), x2,y2)&(x3,y3).
Program checks whether point (x,y) lies inside,outside or on the circle.
ans=0 ==> lie on the circle.
ans=1 ==> lie outside the circle.
ans=-1 ==> lie inside the circle.