Android 座標點是否在圓裡面

 

    public  static  boolean point_in_circle(float x,float y,float center_x,float center_y,float radius){


        float a=(x-center_x);
        float b=(y-center_y);
        float c=radius*radius;
        a=a*a;
        b=b*b;
        if(a+b<=c)return true;
        return false;
    }