Reverse a singly-linked list

reversell.cc

// Assuming a linked list that looks like this:
template <typename T> 
class List {
public:
  // ...
  void reverse();

 private:
     struct Node {
        T value_;
        Node* next_;
    };

    Node* head_;
};

template <typename T>
void List<T>::reverse() {
    // 0 or 1 items in the list
    if (head_ == nullptr || head_->next_ == nullptr) {
        return;
    }

    Node* reversed = nullptr;
    auto current = head_;

    while (current != nullptr) { 
        Node* next = current->next_;
        current->next_ = reversed;
        reversed = current;
        current = next;
    }

    head_  = reversed;
}