我正在尝试定义此运算符重载函数。但是,我从编译器收到此错误:
List.hpp:62:1: error: invalid use of template-name ‘cop4530::List’ without an argument list
List& List<T>::operator=(List&& rhs) // move assingment operator
这是我正在研究的全班。它是一个实现双向链表的类:
template <typename T>
class List {
private:
struct Node {
T data;
Node *prev;
Node *next;
Node(const T & d = T{}, Node *p = nullptr, Node *n = nullptr)
: data{d}, prev{p}, next{n} {}
Node(T && d, Node *p = nullptr, Node *n = nullptr)
: data{std::move(d)}, prev{p}, next{n} {}
};
public:
//nested const_iterator class
class const_iterator {
public:
const_iterator(); // default zero parameter constructor
const T & operator*() const; // operator*() to return element
// increment/decrement operators
const_iterator & operator++();
const_iterator operator++(int);
const_iterator & operator--();
const_iterator operator--(int);
// comparison operators
bool operator==(const const_iterator &rhs) const;
bool operator!=(const const_iterator &rhs) const;
protected:
Node *current; // pointer to node in List
T & retrieve() const; // retrieve the element refers to
const_iterator(Node *p); // protected constructor
friend class List<T>;
};
// nested iterator class
class iterator : public const_iterator {
public:
iterator();
T & operator*();
const T & operator*() const;
// increment/decrement operators
iterator & operator++();
iterator operator++(int);
iterator & operator--();
iterator operator--(int);
protected:
iterator(Node *p);
friend class List<T>;
};
public:
// constructor, desctructor, copy constructor
List(); // default zero parameter constructor
List(const List &rhs); // copy constructor
List(List && rhs); // move constructor
// num elements with value of val
explicit List(int num, const T& val = T{});
// constructs with elements [start, end)
List(const_iterator start, const_iterator end);
// constructs with a copy of each of the elements in the initalizer_list
List (std::initializer_list<T> iList);
~List(); // destructor
// copy assignment operator
const List& operator=(const List &rhs);
// move assignment operator
List & operator=(List && rhs);
// sets list to the elements of the initializer_list
List& operator= (std::initializer_list<T> iList);
// member functions
int size() const; // number of elements
bool empty() const; // check if list is empty
void clear(); // delete all elements
void reverse(); // reverse the order of the elements
T& front(); // reference to the first element
const T& front() const;
T& back(); // reference to the last element
const T& back() const;
void push_front(const T & val); // insert to the beginning
void push_front(T && val); // move version of insert
void push_back(const T & val); // insert to the end
void push_back(T && val); // move version of insert
void pop_front(); // delete first element
void pop_back(); // delete last element
void remove(const T &val); // remove all elements with value = val
template <typename PREDICATE>
void remove_if(PREDICATE pred); // remove all elements for which Predicate pred
// returns true. pred can take in a function object
// print out all elements. ofc is deliminitor
void print(std::ostream& os, char ofc = ' ') const;
iterator begin(); // iterator to first element
const_iterator begin() const;
iterator end(); // end marker iterator
const_iterator end() const;
iterator insert(iterator itr, const T& val); // insert val ahead of itr
iterator insert(iterator itr, T && val); // move version of insert
iterator erase(iterator itr); // erase one element
iterator erase(iterator start, iterator end); // erase [start, end)
private:
int theSize; // number of elements
Node *head; // head node
Node *tail; // tail node
void init(); // initialization
};
我想要定义的功能就是这个:
template < typename T>
List& List<T>::operator=(List&& rhs)
{
std::swap( theSize, rhs.theSize);
std::swap( head, rhs.head);
std::swap( tail, rhs.tail);
return *this;
}
答案 0 :(得分:1)
您忘记添加<T>
:
template <typenameT>
List<T>& List<T>::operator=(List<T>&& rhs)
// ^^^ ^^^
// ^ this one is optional but I prefer it
{
//...
}