C++ Coding Example Usage?

[samsonsite1]

I'm interested in calling this code from C++ code.

Could you please show a C++ coding example how to manually set and fill the vertices and faces variables?
I'm unfamiliar with Eigen library and how to initialize them remains unclear.

btw, this is a very obtuse way of storing and passing simple vector data.

 Eigen::MatrixX3d vertices;
 Eigen::MatrixX3i faces;
 
 // how to fill vertices ??
 // how to fill faces ??

 vector<Eigen::VectorXi> boundary_loops;
 boundary_loops = hole_filling_liepa::find_boundary_loops(faces);

 Eigen::MatrixX3i area_patch;
 area_patch = hole_filling_liepa::fill_hole_liepa(vertices, faces, boundary_loops[0], "area" );

[samsonsite1]

For simplicity sake, let's say I have a list of vertices and faces in this format:

class Vector3 {
public:
    double x;
    double y;
    double z;
};

class Vertex {
public:
   Vector3 point;
};

class Face {
public:
    int i1, i2, i3;
};

std::vector<Vertex> vertices;
std::vector<Face>   faces;

How to load this into Eigen::MatrixX3d and Eigen::MatrixX3i ?