std::forward_list::forward_list

(1) empty container constructor (default constructor)

Constructs an empty container, with no elements.

(2) fill constructor

Constructs a container with n elements. Each element is a copy of val (if provided).

(3) range constructor

Constructs a container with as many elements as the range[first,last), with each element emplace-constructed from its corresponding element in that range, in the same order.

(4) copy constructor (and copying with allocator)

Constructs a container with a copy of each of the elements in fwdlst, in the same order.

(5) move constructor (and moving with allocator)

Constructs a container that acquires the elements of fwdlst.
If alloc is specified and is different from fwdlst's allocator, the elements are moved. Otherwise, no elements are constructed (their ownership is directly transferred).
fwdlst is left in an unspecified but valid state.

(6) initializer list constructor

Constructs a container with a copy of each of the elements in il, in the same order.

参数

alloc

Allocator object.
The container keeps and uses an internal copy of this allocator.
成员类型allocator_typeis the internal allocator type used by the container, defined in forward_list as an alias of its second template parameter (Alloc).
如果已知allocator_typeis an instantiation of the default allocator (which has no state), this is not relevant.

n

Initial container size (i.e., the number of elements in the container at construction).
成员类型size_type是一种无符号整型类型。

val

Value to fill the container with. Each of the n elements in the container is initialized to a copy of this value.
成员类型value_typeis the type of the elements in the container, defined in forward_list as an alias of its first template parameter (T).

first, last

指向范围内初始位置和最终位置的输入迭代器。 使用的范围是[first,last)，它包括first和last之间的所有元素，包括first指向的元素，但不包括last指向的元素。
函数模板参数InputIteratorshall be an input iterator type that points to elements of a type from whichvalue_type对象的类型的元素。

fwdlst

Another forward_list object of the same type (with the same class template arguments), whose contents are either copied or acquired.

il

il
这些对象是从初始化列表声明符自动构造的。
成员类型value_typeis the type of the elements in the container, defined in forward_list as an alias of its first template parameter (T).

示例

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// forward_list constructors
#include <iostream>
#include <forward_list>

int main ()
{
  // constructors used in the same order as described above:

  std::forward_list<int> first;                      // default: empty
  std::forward_list<int> second (3,77);              // fill: 3 seventy-sevens
  std::forward_list<int> third (second.begin(), second.end()); // range initialization
  std::forward_list<int> fourth (third);            // copy constructor
  std::forward_list<int> fifth (std::move(fourth));  // move ctor. (fourth wasted)
  std::forward_list<int> sixth = {3, 52, 25, 90};    // initializer_list constructor

  std::cout << "first:" ; for (int& x: first)  std::cout << " " << x; std::cout << '\n';
  std::cout << "second:"; for (int& x: second) std::cout << " " << x; std::cout << '\n';
  std::cout << "third:";  for (int& x: third)  std::cout << " " << x; std::cout << '\n';
  std::cout << "fourth:"; for (int& x: fourth) std::cout << " " << x; std::cout << '\n';
  std::cout << "fifth:";  for (int& x: fifth)  std::cout << " " << x; std::cout << '\n';
  std::cout << "sixth:";  for (int& x: sixth)  std::cout << " " << x; std::cout << '\n';

  return 0;
}

forward_list constructor examples:
first:
second: 77 77 77
third: 77 77 77
fourth:
fifth: 77 77 77
sixth: 3 52 25 90

复杂度

迭代器有效性

数据竞争

异常安全

另见

forward_list::operator=

赋新值 (公开成员函数)

forward_list::assign

赋新值 (公开成员函数)

forward_list::resize

改变大小 (公开成员函数)

forward_list::clear

清除内容 (公开成员函数)