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#include "list.hh"
List::List()
: nb_elts_{ 0 }
{}
void List::push_front(int i)
{
nb_elts_++;
if (nb_elts_ == 1)
{
first_ = std::make_shared<Node>(i);
last_ = first_;
return;
}
std::shared_ptr<Node> ns = std::make_shared<Node>(i);
ns->set_next(first_);
first_->set_prev(ns);
first_ = ns;
}
std::optional<int> List::pop_front()
{
if (nb_elts_ == 0)
{
return std::nullopt;
}
nb_elts_--;
int res = first_->get_val();
if (nb_elts_ == 0)
{
first_ = nullptr;
last_ = nullptr;
return res;
}
std::shared_ptr<Node> tmp = first_->get_next();
first_->set_next(nullptr);
tmp->set_prev(nullptr);
first_ = tmp;
return res;
}
void List::push_back(int i)
{
nb_elts_++;
if (nb_elts_ == 1)
{
first_ = std::make_shared<Node>(i);
last_ = first_;
return;
}
std::shared_ptr<Node> ns = std::make_shared<Node>(i);
ns->set_prev(last_);
last_->set_next(ns);
last_ = ns;
}
std::optional<int> List::pop_back()
{
if (nb_elts_ == 0)
{
return std::nullopt;
}
nb_elts_--;
int res = last_->get_val();
if (nb_elts_ == 0)
{
first_ = nullptr;
last_ = nullptr;
return res;
}
std::shared_ptr<Node> tmp = last_->get_prev();
last_->set_prev(nullptr);
tmp->set_next(nullptr);
last_ = tmp;
return res;
}
void List::print(std::ostream& os) const
{
if (nb_elts_ == 0)
return;
os << first_->get_val();
for (Node* node = first_->get_next().get(); node;
node = node->get_next().get())
{
os << " " << node->get_val();
}
// os << "\n";
}
size_t List::length() const
{
return nb_elts_;
}
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