如何在CGAL中获得一般多边形集的面积？

#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/Polygon_with_holes_2.h>
#include <CGAL/Boolean_set_operations_2.h>

typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;
typedef Kernel::Point_2 Point_2;
typedef CGAL::Polygon_2<Kernel> Polygon_2;
typedef CGAL::Polygon_with_holes_2<Kernel> Polygon_with_holes_2;

double getPolygonSetArea(const std::vector<Polygon_2>& polygons)
{
    // 创建一个Polygon_with_holes_2对象
    Polygon_with_holes_2 polygonSet;

    // 添加多边形和内部孔洞
    for (const auto& polygon : polygons)
    {
        polygonSet.add_hole(polygon.holes_begin(), polygon.holes_end());
    }

    // 计算多边形集合的面积
    double area = CGAL::to_double(polygonSet.area());

    return area;
}

int main()
{
    // 创建多边形集合
    std::vector<Polygon_2> polygons;

    // 添加多边形到集合中
    // ...

    // 调用函数计算面积
    double area = getPolygonSetArea(polygons);

    // 输出面积值
    std::cout << "Polygon set area: " << area << std::endl;

    return 0;
}