std::front_inserter

 

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indirectly_readable (C++20) indirectly_writable (C++20) weakly_incrementable (C++20) incrementable (C++20) is-integer-like is-signed-integer-like (C++20)(C++20)	sentinel_for (C++20) sized_sentinel_for (C++20) input_iterator (C++20) output_iterator (C++20) input_or_output_iterator (C++20)	forward_iterator (C++20) bidirectional_iterator (C++20) random_access_iterator (C++20) contiguous_iterator (C++20)
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indirectly_unary_invocableindirectly_regular_unary_invocable (C++20)(C++20)	indirect_unary_predicate (C++20) indirect_binary_predicate (C++20)	indirect_equivalence_relation (C++20) indirect_strict_weak_order (C++20)
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reverse_iterator make_reverse_iterator (C++14) move_iterator (C++11) make_move_iterator (C++11) default_sentinel_tdefault_sentinel (C++20)(C++20) unreachable_sentinel_tunreachable_sentinel (C++20)(C++20)	front_insert_iterator back_insert_iterator inserter insert_iterator front_inserter back_inserter move_sentinel (C++20)	common_iterator (C++20) counted_iterator (C++20) basic_const_iterator (C++23) const_iterator (C++23) const_sentinel (C++23) make_const_iterator (C++23) make_const_sentinel (C++23)
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迭代器操作 advance distance prev (C++11)   next (C++11) ranges::advance (C++20) ranges::distance (C++20) ranges::prev (C++20) ranges::next (C++20)	范围访问 begincbegin (C++11)(C++14) rbegincrbegin (C++14)(C++14)   endcend (C++11)(C++14) rendcrend (C++14)(C++14)   sizessize (C++17)(C++20) empty (C++17) data (C++17)

 

在标头 <iterator> 定义
template< class Container > std::front_insert_iterator<Container> front_inserter( Container& c );		(C++20 起为 constexpr)

front_inserter 是便利函数模板，为容器 c 构造 std::front_insert_iterator，并拥有从实参类型推导的类型。

参数

c

-

支持 push_front 操作的容器

返回值

能用于向容器 c 开头添加元素的 std::front_insert_iterator。

可能的实现

template<class Container> std::front_insert_iterator<Container> front_inserter( Container& c ) { return std::front_insert_iterator<Container>(c); }

示例

运行此代码

#include <algorithm>
#include <deque>
#include <iostream>
#include <iterator>
#include <vector>
 
int main()
{
    std::vector<int> v{1, 2, 3, 4, 5};
    std::deque<int> d;
    std::copy(v.begin(), v.end(), std::front_inserter(d));
    for (int n : d)
        std::cout << n << ' ';
    std::cout << '\n';
}

输出：

5 4 3 2 1

参阅

front_insert_iterator	用于在容器头部插入的迭代器适配器 (类模板)
back_inserter	创建拥有从实参推出的类型的 std::back_insert_iterator (函数模板)
inserter	创建拥有从实参推出的类型的 std::insert_iterator (函数模板)