std::unordered_map insert error shared_ptr c++

Question

I am using std::unordered_map for the first time and am having a problem inserting into the map I have created. ClassA header: ``` Class ClassA { public: void func(); private: std::unordered_map> map; } ``` ClassA cpp: ``` void ClassA::func() { map = std::unordered_map>(); map.insert("string", std::make_shared()); } ``` I am getting error c2664 std::_List_iterator<_Mylist> std::_Hash<_Traits>::insert(std::_List_const_iterator<_Mylist>,std::pair<_Ty1,_Ty2> &&)' : cannot convert parameter 1 from 'const char [17]' to 'std::_List_const_iterator<_Mylist>' Any ideas?

Accepted Answer

The problem is not with the `shared_ptr`, but with the `string` key. Explicit instantiation will solve this problem. You also need to insert a `pair` consisting of the key and the value, not a key and a value seperately:

```
map.insert(std::make_pair (std::string("string"), std::make_shared<ClassB>()));
```

See also this related answer for a more novel, albiet more complex solution.

std::unordered_map insert error shared_ptr c++

Solution

Problem