CODEWITHSUNDEEP
c++dictionaryiteratorbehaviorerase
Winjun
Winjun

Reputation: 31

Erase using iterator on C++ map

I am experiencing the following behavior: I create a map, do a find on the key and delete the map entry. After erase, I print the elements using the iterator and I expected it to dump core but it works.

Why does it work?

     typedef std::pair<std::string, int> pair;
    std::map<pair, int> nameidCntMap;

    pair pair1("ABC", 139812);
    pair pair2("XYZ", 139915);
    pair pair3("PQR", 139098);


    nameidCntMap.insert(std::make_pair(pair1, 1));
    nameidCntMap.insert(std::make_pair(pair2, 1));
    nameidCntMap.insert(std::make_pair(pair3, 1));

    std::map<pair, int>::iterator it = nameidCntMap.find(pair1);
    if (it != nameidCntMap.end())
    {
            symsrcidCntMap.erase(it);
   
            std::cout<<"Pair::first: "<<it->first.first << "Pair::second: "<<it->first.second<<"map second:"<<it->second<<std::endl;
    }

Upvotes: 3

Views: 142

Answers (1)

eerorika
eerorika

Reputation: 238461

Why does it work?

It doesn't "work".

Behaviour of the program is undefined.

expected it to dump core

Your expectation is misguided. The program isn't defined to "dump core" when you indirect through an invalid iterator. No behaviour is defined for such program. As such, any behaviour is possible. Among all possible behaviours, there is the possibility that the behaviour is what you didn't expect, or what you consider to be "working".

Upvotes: 4

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