Circle.java

public class Circle {

    private int id;
    private static int circleCount = 0;
    private final double PI = 3.1415;
    public int radius;

    public Circle(int radius){
        circleCount++;
        this.id = circleCount;
        this.radius = radius;
    }

    public static void main(String[] args){
        Circle circle = new Circle(5);
        int actualArea = circle.area(false); // should be 78
        int integerArea = circle.area(true); // should be 81
    }

    // A.K.A Gauss Circle Problem
    public int area(){
        int result = 0;
        for(int x=-radius; x<=radius; x++){
            for(int y=-radius; y<=radius; y++){
                if(x*x + y*y <= radius*radius)
                    result++;
            }
        }
        return result;
    }

    public int area(boolean integerArea){
        try {
            getCircleCount();
            if (integerArea)
                return area();
        }
        catch(Exception exception){

        }
        return (int) (1.0*radius*radius*PI);
    }


    public static int getCircleCount(){
        return circleCount;
    }

}