How can I represent a vector equation of a line segment in C++?

Question

I am working with computer graphics.

I would like to represent a line with two end points, and, then I would like my Line2d class to have a method that

Answer 1

If you want to convert a line segment to a vector, you have to be aware that there is no "universal semantic" for the conversion, it is up to you to define what the conversion means. That said, I assume you want a vector with the same (Euclidean) norm as the length of the line segment and pointing in the same direction, i.e. something like this:

class LineSegment2d
{
   ....
   Vector2d getVector() const {
      return Vector2d(end) - Vector2d(start);
   }
};

In other words, offset the line segment to the origin point of the coordinate system. The end point can then be converted to a vector.

EDIT: After understanding a bit more about why you want this, you might be looking for another representation

class LineSegment2d
{
   ....
   Vector2d getVector() const {
      return Vector2d(end);
   }
};

This will get you one vector for each line segment: the end point. If your polygons consist of connected line segments, this will give you all the vertices in the polygon.