One example of STL map

#include <map>
#include <iostream>
#include <string.h> //for memcmp
using namespace std;

typedef struct{
    int connId;
    int ueRef;
    int rncId;
}UEREF_RNCID;

struct classcomp {
    bool operator() (const UEREF_RNCID & l, const UEREF_RNCID & r) const
    {
        return memcmp(&l, &r, sizeof(UEREF_RNCID)) < 0;
    }
};

UEREF_RNCID assignKey(int connId, int ueRef, int rncId)
{
    UEREF_RNCID tempKey;
    tempKey.connId = connId;
    tempKey.ueRef = ueRef;
    tempKey.rncId = rncId;
    return tempKey;
}

int main(int argc, char **argv)
{
    map<UEREF_RNCID, int, classcomp> m;
    map<UEREF_RNCID, int, classcomp>::iterator it;
    UEREF_RNCID key1, key2;
    key1 = assignKey(-1,1,1);
    key2 = assignKey(-1,2,1);
    m[key1] = 0; //index is 0
    m[key2] = 1; //index is 1
    it = m.find(key1);
    cout << it->second << endl; //will print 1
    return 0;
}