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c++11unique-ptr

How to remove unique_ptr by pointer from a container?

Creating an object and giving ownership to a container using a unique_ptr is no problem. How would one remove an element by raw pointer?

std::set<std::unique_ptr<MyClass>> mySet;

MyClass *myClass = new MyClass();
mySet.insert(std::unique_ptr<MyClass>(myClass));

// remove myClass from mySet?
Solution

  • You will need to find the iterator corresponding to the myClass element and then pass that iterator to mySet.erase(). The iterator may be found using the std::find_if algorithm with a custom Predicate functor that understands how to dereference unique_ptr and compare it to the raw pointer myClass.

    You can not use the overloaded size_t set::erase ( const key_type& x ); since the raw pointer (even if wrapped in a temporary unique_ptr) will not be found in mySet.