std::counted_iterator<I>::operator++,+,+=,--,-,-=

 

C++

編譯器支援

自由（freestanding）與宿主（hosted）

語言

標準庫

標準庫標頭檔案

具名要求

特性測試宏 (C++20)

語言支援庫

概念庫 (C++20)

診斷庫

記憶體管理庫

超程式設計庫 (C++11)

通用工具庫

容器庫

迭代器庫

範圍庫 (C++20)

演算法庫

字串庫

文字處理庫

數值庫

日期和時間庫

輸入/輸出庫

檔案系統庫 (C++17)

併發支援庫 (C++11)

執行控制庫 (C++26)

技術規範

符號索引

外部庫

 

迭代器庫

迭代器概念
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)
迭代器原語
input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tagcontiguous_iterator_tag (C++20)	iter_value_titer_difference_titer_reference_titer_const_reference_titer_rvalue_reference_titer_common_reference_t (C++20)(C++20)(C++20)(C++23)(C++20)(C++20)	iterator (C++17 中已棄用) iterator_traits incrementable_traits (C++20) indirectly_readable_traits (C++20)
演算法概念與工具
間接可呼叫概念
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)
常用演算法要求
indirectly_movable (C++20) indirectly_movable_storable (C++20) indirectly_copyable (C++20)	indirectly_copyable_storable (C++20)   indirectly_swappable (C++20) indirectly_comparable (C++20)	permutable (C++20) mergeable (C++20) sortable (C++20)
工具
indirect_result_t (C++20)	projected (C++20)	projected_value_t (C++26)
迭代器介面卡
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)
流迭代器 istream_iterator    ostream_iterator istreambuf_iterator ostreambuf_iterator	迭代器定製點 ranges::iter_move (C++20) ranges::iter_swap (C++20)
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)	範圍訪問 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)

 

std::counted_iterator

成員函式

counted_iterator::counted_iterator

counted_iterator::operator=

counted_iterator::base

counted_iterator::count

counted_iterator::operator*counted_iterator::operator->

counted_iterator::operator[]

counted_iterator::operator++counted_iterator::operator++(int)counted_iterator::operator+counted_iterator::operator+=counted_iterator::operator--counted_iterator::operator--(int)counted_iterator::operator-counted_iterator::operator-=

非成員函式

operator==operator<=> (C++20)(C++20)

operator==(default_sentinel_t) (C++20)

operator+ (C++20)

operator- (C++20)

operator-(default_sentinel_t) (C++20)

iter_move (C++20)

iter_swap (C++20)

輔助類

iterator_traits<std::counted_iterator> (C++20)

 

constexpr counted_iterator& operator++();	(1)	(C++20 起)
constexpr decltype(auto) operator++( int );	(2)	(C++20 起)
constexpr counted_iterator operator++( int )     requires std::forward_iterator<I>;	(3)	(C++20 起)
constexpr counted_iterator& operator--()     requires std::bidirectional_iterator<I>;	(4)	(C++20 起)
constexpr counted_iterator operator--( int )     requires std::bidirectional_iterator<I>;	(5)	(C++20 起)
constexpr counted_iterator operator+( std::iter_difference_t<I> n ) const     requires std::random_access_iterator<I>;	(6)	(C++20 起)
constexpr counted_iterator& operator+=( std::iter_difference_t<I> n )     requires std::random_access_iterator<I>;	(7)	(C++20 起)
constexpr counted_iterator operator-( std::iter_difference_t<I> n ) const     requires std::random_access_iterator<I>;	(8)	(C++20 起)
constexpr counted_iterator& operator-=( std::iter_difference_t<I> n )     requires std::random_access_iterator<I>;	(9)	(C++20 起)

遞增或遞減底層迭代器 current 和到末尾的距離 length。

如果 length 將被設定為負值，這些函式的行為是未定義的。

1) 前置遞增一。等價於 ++current; --length; return *this;。

2) 後置遞增一。等價於 --length; try { return current++; } catch(...) { ++length; throw; }。

3) 後置遞增一。等價於 counted_iterator temp{*this}; ++*this; return temp;。

4) 前置遞減一。等價於 --current; ++length; return *this;。

5) 後置遞減一。等價於 counted_iterator temp{*this}; --*this; return temp;。

6) 返回一個迭代器介面卡，它前進 n 位。等價於 return counted_iterator(current + n, length - n);。

7) 將迭代器介面卡前進 n 位。等價於 current += n; length -= n; return *this;。

8) 返回一個迭代器介面卡，它前進 -n 位。等價於 return counted_iterator(current - n, length + n);。

9) 將迭代器介面卡前進 -n 位。等價於 current -= n; length += n; return *this;。

引數

n

-

遞增或遞減迭代器介面卡的位置數

返回值

1) *this

2,3) 更改前建立的 *this 的副本。

4) *this

5) 更改前建立的 *this 的副本。

6) 一個前進 n 位的迭代器介面卡。

7) *this

8) 一個前進 -n 位的迭代器介面卡。

9) *this

示例

執行此程式碼

#include <cassert>
#include <initializer_list>
#include <iterator>
 
int main()
{
    const auto v = {1, 2, 3, 4, 5, 6};
    std::counted_iterator<std::initializer_list<int>::iterator> it1{v.begin(), 5};
 
    ++it1;              assert(*it1 == 2 && it1.count() == 4); // (1)
    auto it2 = it1++;   assert(*it2 == 2 && *it1 == 3);        // (3)
    --it1;              assert(*it1 == 2 && it1.count() == 4); // (4)
    auto it3 = it1--;   assert(*it3 == 2 && *it1 == 1);        // (5)
    auto it4 = it1 + 3; assert(*it4 == 4 && it4.count() == 2); // (6)
    auto it5 = it4 - 3; assert(*it5 == 1 && it5.count() == 5); // (8)
    it1 += 3;           assert(*it1 == 4 && it1.count() == 2); // (7)
    it1 -= 3;           assert(*it1 == 1 && it1.count() == 5); // (9)
}

參閱

operator+ (C++20)	前進迭代器 (函式模板)
operator- (C++20)	計算兩個迭代器介面卡之間的距離 (函式模板)