Polygon centroid

#include <bits/stdc++.h>
using namespace std;
 
pair<double, double> find_Centroid(vector<pair<double, double> >& v)
{
    pair<double, double> ans = { 0, 0 };
     
    int n = v.size();
    double signedArea = 0;
     
    // For all vertices
    for (int i = 0; i < v.size(); i++) {
         
        double x0 = v[i].first, y0 = v[i].second;
        double x1 = v[(i + 1) % n].first, y1 =
                            v[(i + 1) % n].second;
                             
        // Calculate value of A
        // using shoelace formula
        double A = (x0 * y1) - (x1 * y0);
        signedArea += A;
         
        // Calculating coordinates of
        // centroid of polygon
        ans.first += (x0 + x1) * A;
        ans.second += (y0 + y1) * A;
    }
 
    signedArea *= 0.5;
    ans.first = (ans.first) / (6 * signedArea);
    ans.second = (ans.second) / (6 * signedArea);
 
    return ans;
}