std::counted_iterator<I>:: operator++,+,+=,--,-,-=
From cppreference.com
<
cpp
|
iterator
|
counted iterator
|
constexpr
counted_iterator
&
operator
++
(
)
;
|
(1) | (since C++20) |
|
constexpr
decltype
(
auto
)
operator
++
(
int
)
;
|
(2) | (since C++20) |
|
constexpr
counted_iterator operator
++
(
int
)
requires std:: forward_iterator < I > ; |
(3) | (since C++20) |
|
constexpr
counted_iterator
&
operator
--
(
)
requires std:: bidirectional_iterator < I > ; |
(4) | (since C++20) |
|
constexpr
counted_iterator operator
--
(
int
)
requires std:: bidirectional_iterator < I > ; |
(5) | (since C++20) |
|
constexpr
counted_iterator operator
+
(
std::
iter_difference_t
<
I
>
n
)
const
requires std:: random_access_iterator < I > ; |
(6) | (since C++20) |
|
constexpr
counted_iterator
&
operator
+
=
(
std::
iter_difference_t
<
I
>
n
)
requires std:: random_access_iterator < I > ; |
(7) | (since C++20) |
|
constexpr
counted_iterator operator
-
(
std::
iter_difference_t
<
I
>
n
)
const
requires std:: random_access_iterator < I > ; |
(8) | (since C++20) |
|
constexpr
counted_iterator
&
operator
-
=
(
std::
iter_difference_t
<
I
>
n
)
requires std:: random_access_iterator < I > ; |
(9) | (since C++20) |
Increments or decrements the underlying iterator
current
and the distance to the end
length
.
The behavior of these functions is undefined if the
length
would be set to a minus value.
1)
Pre-increments by one. Equivalent to
++
current
;
--
length
;
return
*
this
;
.
2)
Post-increments by one. Equivalent to
--
length
;
try
{
return
current
++
;
}
catch
(
...
)
{
++
length
;
throw
;
}
.
3)
Post-increments by one. Equivalent to
counted_iterator temp
{
*
this
}
;
++*
this
;
return
temp
;
.
4)
Pre-decrements by one. Equivalent to
--
current
;
++
length
;
return
*
this
;
.
5)
Post-decrements by one. Equivalent to
counted_iterator temp
{
*
this
}
;
--*
this
;
return
temp
;
.
6)
Returns an iterator adaptor which is advanced by
n
. Equivalent to
return
counted_iterator
(
current
+
n, length
-
n
)
;
.
7)
Advances the iterator adaptor by
n
. Equivalent to
current
+
=
n
;
length
-
=
n
;
return
*
this
;
.
8)
Returns an iterator adaptor which is advanced by
-
n
. Equivalent to
return
counted_iterator
(
current
-
n, length
+
n
)
;
.
9)
Advances the iterator adaptor by
-
n
. Equivalent to
current
-
=
n
;
length
+
=
n
;
return
*
this
;
.
Parameters
| n | - | the number of positions to increment or decrement the iterator adaptor |
Return value
1)
*
this
2,3)
A copy of
*
this
that was made before the change.
4)
*
this
5)
A copy of
*
this
that was made before the change.
6)
An iterator adaptor which is advanced by
n
.
7)
*
this
8)
An iterator adaptor which is advanced by
-
n
.
9)
*
this
Example
Run this code
#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) }
See also
|
(C++20)
|
advances the iterator
(function template) |
|
(C++20)
|
computes the distance between two iterator adaptors
(function template) |