I have create a list of point that I get from an image. But the problem that I have many images so I want to create a list of list. My idea is to create a list of string (that contain the name of images) and add the list of point to this list (every image of the string list contain the list of point of that images). I don't know how to do it. this is the first time that I manipulate lists.

This is what i did so far : 

```
struct Point
{
    double x, y;
};
list<Point> landmarks;
list<string> image_name;

for (loop over the images that i have in my folder)
{
    for (loop over point in every image in the folder image)
    {
        Point p;
        p.x = it_shapeROI->roi.pXmin;
        p.y = it_shapeROI->roi.pYmin;
        landmarks.push_back( p ); // list of point in one image
    }
     // Here I want to add to the list of string the list of point.
     // So I will have at the end a list of string (image name)
     // that contain for every name a list of point of that images.
}

```