C++ Program to Implement Slicker Algorithm that avoids Triangulation to Find Area of a Polygon

Code:

#include    iostream

using namespace std;

const int MAXPOLY = 200;
double EPSILON = 0.000001;

class Point
{
    private:
    public:
        double x, y;
};

class Polygon
{
    private:
    public:
        Point p[MAXPOLY];
        int n;

        Polygon()
        {
            for (int i = 0; i < MAXPOLY; i++)
                Point p[i];// = new Point();
        }
};

double area(Polygon p)
{
    double total = 0;
    for (int i = 0; i < p.n; i++)
    {
        int j = (i + 1) % p.n;
        total += (p.p[i].x * p.p[j].y) - (p.p[j].x * p.p[i].y);
    }
    return total / 2;
}

int main(int argc, char **argv)
{
    Polygon p;

    cout << "Enter the number of points in Polygon: ";
    cin >> p.n;
    cout << "Enter the coordinates of each point: ";
    for (int i = 0; i < p.n; i++)
    {
        cin >> p.p[i].x;
        cin >> p.p[i].y;
    }

    double a = area(p);
    if (a > 0)
        cout << "The Area of Polygon with " << (p.n)
                << " points using Slicker Algorithm is : " << a;
    else
        cout << "The Area of Polygon with " << p.n
                << " points using Slicker Algorithm is : " << (a * -1);
}


Output:

Enter the number of points in Polygon: 4
Enter the coordinates of each point:
1 1
1 6
6 6
6 1
The Area of Polygon with 4 points using Slicker Algorithm is : 25

Enter the number of points in Polygon: 
5
Enter the coordinates of each point:
1 2
4 5
9 8
3 2
1 5
The Area of Polygon with 5points using Slicker Algorithm is : 6.0
------------------
(program exited with code: 0)
Press return to continue



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