CODEWITHSUNDEEP
c++oopstdmultimap
some_math_guy
some_math_guy

Reputation: 333

Trying to pass data from a multimap to a map is not working as suggested

In this post Convert a multi_key map into a "normal" map joining the multiple keys

They suggest how to convert a multimap to the map by passing the values of the first to the second one. I tried that in my code, but it doesn't work:

multimap<double, Point>::iterator it;
  
for(it = _mapIntersectionVertices.begin(); it != _mapIntersectionVertices.end(); ++it)
{
  _mapNewPoints[it->first].insert(it->second);
}

I get the error "no member named 'insert' in 'Point'" I don't know why, I am not trying to call a method, just following the example in the post. As a side thing I am not very comfortable with the fact they use the same iterator for the map and the multimap inside the for, but when using instead a map iterator it2 to do:

 _mapNewPoints[it2->first].insert(it->second)

nothing changes

where i have the following attributes in some class I am trying to fill in.

multimap<double, Point> _mapIntersectionVertices;
map<double, Point> _mapNewPoints;

and the Point class is:

class Point
{
    private:
        Vector2d _coordinates; //using Eigen library

    public:
        int _label;
        Point(const double x = 0.0, const double y = 0.0);
        Point(Vector2d coordinates);

        void setCoordinates(const double x, const double y) {_coordinates(x, y);}
        const Vector2d& getCoordinates() const {return _coordinates;}


};

I want to copy the content of the multimap into the map, so that I can add more data to the later without messing with the first one and in a easier way than if _mapNewPoints were declared as a multimap( using the [] operator that is available for a map but not for a multimap).

How do I solve this?

Upvotes: 0

Views: 182

Answers (1)

anastaciu
anastaciu

Reputation: 23792

_mapNewPoints[it->first].insert would imply that Point has an insert method which is not the case. I believe you may want something like this:

for (it = _mapIntersectionVertices.begin(); it != _mapIntersectionVertices.end(); ++it)
{
    _mapNewPoints.insert(*it);
}

Upvotes: 1

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