如何处理C ++中包含列表的嵌套数据结构

Question

I have two data structure one containing the other as seen, I want to loop on all lineSegmentClusters, access the list of candidatePointList of each and finally access the lineSegmentId of each in that list.

typedef struct CandidateClusterPoint {
    float orderingValue;
    int lineSegmentId;
    bool startPointFlag;
} CandidateClusterPoint;

typedef struct LineSegmentCluster {
    int lineSegmentClusterId;                  
    int nLineSegments;                         
    list<CandidateClusterPoint> candidatePointList;                              
    vector<CMDPoint> clusterPointArray;
    bool enabled;
} LineSegmentCluster;

what I tried is:

list<CandidateClusterPoint>::iterator iter;
for (int i = 0; i < m_currComponentId; i++)        
{

    if (m_lineSegmentClusters[i].enabled)

    {
        for(iter=m_lineSegmentClusters[i].candidatePointList.begin() ; iter!=m_lineSegmentClusters[i].candidatePointList.end() ; iter++)            
        {   

        }

but I cant access the lineSegmentID of each one what do I need to write to be able to access them one after the other?

Answer 1

The iterator is not your actual struct but a class that contains a reference to it. You can access them by using the * operator like this:

(*iter).lineSegmentID = <your value>;

Answer 2

Have you tried using pointers? In your LineSegmentCluster class, define this as the list:

list<CandidateClusterPoint*> candidatePointList;

Then in your main function do this (always use consts if you are not changing the variables the iterator is pointing to):

list<CandidateClusterPoint*>::const_iterator iter;
for (int i = 0; i < m_currComponentId; i++)        
{
    if (m_lineSegmentClusters[i].enabled)
    {
        for(itertry=m_lineSegmentClusters[i].candidatePointList.begin() ; itertry!=m_lineSegmentClusters[i].candidatePointList.end() ; itertry++)           
        {   
            cout << (*iter)->lineSegmentId // This should be where you access it   
        }
     }
}