具有std :: unique_ptr的二叉树

Question

I'm actually using std::unique_ptr in order to create a binary tree.

In fact, I use an algorithm tour, which from a distance matrix, calculates the shortest path ! In my algorithm, I found myself confronted with the problem of std::move() with std::unique_ptr .

My tree is built, but only on the root node and don't "make branch".

Here the code where I have the problem :

node = std::move(node.get()->addChild());

The function addChild returns a reference of the new child (= std::unique_ptr<Node>) .

I really need to "change" node in order to complete my algorithm. So, How can I fix it ?

Answer 1

Change addChild to return the new node's unique_ptr by value instead of returning a reference. The result will be an rvalue without requiring a cast with std::move . In your current code, you pass an lvalue reference to std::move which results in it still being an lvalue reference and attempting to invoke the copy constructor instead of move constructor of std::unique_ptr .