operator-(std::counted_iterator)

From cppreference.com

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros(C++20)
Language support library
Concepts library(C++20)
Diagnostics library
Memory management library
Metaprogramming library(C++11)
General utilities library
Containers library
Iterators library
Ranges library(C++20)
Algorithms library
Strings library
Text processing library
Numerics library
Date and time library
Input/output library
Filesystem library(C++17)
Concurrency support library(C++11)
Execution control library(C++26)
Technical specifications
Symbols index
External libraries

[edit]

Iterator library

Iterator concepts

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)

Iterator primitives

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 (deprecated in C++17)
iterator_traits
incrementable_traits (C++20)
indirectly_readable_traits (C++20)

Algorithm concepts and utilities

Indirect callable concepts

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)

Common algorithm requirements

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)

(C++20)

(C++20)

(C++26)

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)

Stream iterators

istream_iterator
ostream_iterator

istreambuf_iterator
ostreambuf_iterator

Iterator customization points
ranges::iter_move (C++20)
ranges::iter_swap (C++20)

Iterator operations

advance
distance
prev (C++11)
next (C++11)

ranges::advance (C++20)
ranges::distance (C++20)
ranges::prev (C++20)
ranges::next (C++20)

Range access

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)

[edit]

std::counted_iterator

Member functions
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-=
Non-member functions
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)
Helper classes
iterator_traits<std::counted_iterator> (C++20)

[edit]

template<std::common_with<I> I2> friendconstexprstd::iter_difference_t<I2> operator-( const counted_iterator& x,const counted_iterator<I2>& y);		(since C++20)

Computes the distance between two iterator adaptors.

The behavior is undefined ifx andy do not point to elements of the same sequence. That is, there must exist somen such thatstd::next(x.base(), x.count()+ n) andstd::next(y.base(), y.count()+ n) refer to the same element.

This function template is not visible to ordinaryunqualified orqualified lookup, and can only be found byargument-dependent lookup when std::counted_iterator<I> is an associated class of the arguments.

[edit]Parameters

x, y

iterator adaptors to compute the difference of

[edit]Return value

y.count()- x.count()

[edit]Notes

Since thelength counts down, not up, the order of the arguments ofoperator- in the underlying expression is reversed, i.e.y islhs andx isrhs.

[edit]Example

Run this code

#include <initializer_list>#include <iterator> int main(){staticconstexprauto v={1,2,3,4,5,6};constexprstd::counted_iterator<std::initializer_list<int>::iterator>        it1{v.begin(),5},        it2{it1+3},        it3{v.begin(),2};     static_assert(it1- it2==-3);    static_assert(it2- it1==+3);//  static_assert(it1 - it3 == -3); // UB: operands of operator- do not refer to// elements of the same sequence}

[edit]See also

operator++operator++(int)operator+=operator+operator--operator--(int)operator-=operator-	advances or decrements the`counted_iterator` (public member function)[edit]
operator+ (C++20)	advances the iterator (function template)[edit]
operator-(std::default_sentinel_t) (C++20)	computes the signed distance to the end (function template)[edit]

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/iterator/counted_iterator/operator-&oldid=159835"

Movatterモバイル変換

cppreference.com

Namespaces

Variants

Views

Actions

operator-(std::counted_iterator)

Contents

[edit]Parameters

[edit]Return value

[edit]Notes

[edit]Example

[edit]See also

Navigation

Toolbox