cpp/iterator/back insert iterator: Difference between revisions
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{{cpp/iterator/back_insert_iterator/navbar}} | {{cpp/iterator/back_insert_iterator/navbar}} | ||
{{dcl begin}} | {{dcl begin}} | ||
{{dcl header | iterator}} | {{dcl header|iterator}} | ||
{{dcl rev begin}} | {{dcl rev begin}} | ||
{{dcl | until=c++17 | 1= | {{dcl|until=c++17|1= | ||
template< class Container > | template< class Container > | ||
class back_insert_iterator : public std::iterator< std::output_iterator_tag, | class back_insert_iterator | ||
: public std::iterator<std::output_iterator_tag, void, void, void, void> | |||
}} | }} | ||
{{dcl | since=c++17 | 1= | {{dcl|since=c++17|1= | ||
template< class Container > | template< class Container > | ||
class back_insert_iterator; | class back_insert_iterator; | ||
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{{dcl end}} | {{dcl end}} | ||
{{tt|std::back_insert_iterator}} is a {{named req|OutputIterator}} that appends to a container for which it was constructed. The container's {{tt|push_back()}} member function is called whenever the iterator (whether dereferenced or not) is assigned to. Incrementing the {{tt|std::back_insert_iterator}} is a no-op. | {{tt|std::back_insert_iterator}} is a {{named req|OutputIterator}} that appends to a container for which it was constructed. The container's {{tt|push_back()}} member function is called whenever the iterator (whether dereferenced or not) is assigned to. Incrementing the {{tt|std::back_insert_iterator}} is a no-op. | ||
{{cpp/iterator/iterator/inherit|std::output_iterator_tag|void|void|void|void|ext= | {{cpp/iterator/iterator/inherit|std::output_iterator_tag|void|void|void|void|ext= | ||
{{dsc | {{tt|container_type}} | {{tt|Container}}}} | {{dsc|{{tt|container_type}}|{{tt|Container}}}} | ||
}} | }} | ||
===Member functions=== | ===Member functions=== | ||
{{dsc begin}} | {{dsc begin}} | ||
{{dsc inc | cpp/iterator/inserter/dsc constructor | back_insert_iterator}} | {{dsc inc|cpp/iterator/inserter/dsc constructor|back_insert_iterator}} | ||
{{dsc inc | cpp/iterator/inserter/dsc operator{{=}} | back_insert_iterator}} | {{dsc inc|cpp/iterator/inserter/dsc operator{{=}}|back_insert_iterator}} | ||
{{dsc inc | cpp/iterator/inserter/dsc operator* | back_insert_iterator}} | {{dsc inc|cpp/iterator/inserter/dsc operator*|back_insert_iterator}} | ||
{{dsc inc | cpp/iterator/inserter/dsc operator_arith | back_insert_iterator}} | {{dsc inc|cpp/iterator/inserter/dsc operator_arith|back_insert_iterator}} | ||
{{dsc end}} | {{dsc end}} | ||
===Member objects=== | ===Member objects=== | ||
{{dsc begin}} | {{dsc begin}} | ||
{{dsc hitem | Member name | Definition}} | {{dsc hitem|Member name|Definition}} | ||
{{dsc | {{tt|container}} {{mark|protected}} | a pointer of type {{tt|Container*}} }} | {{dsc|{{tt|container}} {{mark|protected}}|a pointer of type {{tt|Container*}}}} | ||
{{dsc end}} | {{dsc end}} | ||
===Example=== | ===Example=== | ||
{{example | {{example | ||
|code= | |||
#include <iostream> | #include <iostream> | ||
#include <iterator> | #include <iterator> | ||
#include <vector> | #include <vector> | ||
int main() | int main() | ||
{ | { | ||
std::vector<int> v; | |||
std::generate_n( | |||
std::back_insert_iterator<std::vector<int>>(v), | |||
// : | |||
std::back_insert_iterator(v) | |||
10, | |||
[n = 0]() mutable { return ++n; } | |||
); | |||
for (int n : v) | |||
std::cout << n << ' '; | |||
std::cout << '\n'; | |||
} | } | ||
|output= | |||
1 2 3 4 5 6 7 8 9 10 | 1 2 3 4 5 6 7 8 9 10 | ||
}} | }} | ||
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===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
{{dsc inc | cpp/iterator/dsc back_inserter}} | {{dsc inc|cpp/iterator/dsc back_inserter}} | ||
{{dsc inc | cpp/iterator/dsc front_insert_iterator}} | {{dsc inc|cpp/iterator/dsc front_insert_iterator}} | ||
{{dsc inc | cpp/iterator/dsc insert_iterator}} | {{dsc inc|cpp/iterator/dsc insert_iterator}} | ||
{{dsc end}} | {{dsc end}} | ||
{{langlinks|de|es|fr|it|ja|pt|ru|zh}} | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | ||
Latest revision as of 16:26, 18 September 2023
| Defined in header <iterator>
|
||
template< class Container >
class back_insert_iterator
: public std::iterator<std::output_iterator_tag, void, void, void, void>
|
(until C++17) | |
template< class Container >
class back_insert_iterator;
|
(since C++17) | |
std::back_insert_iterator is a LegacyOutputIterator that appends elements to a container for which it was constructed. The container's push_back() member function is called whenever the iterator (whether dereferenced or not) is assigned to. Incrementing the std::back_insert_iterator is a no-op.
Member types
| Member type | Definition | ||||
iterator_category
|
std::output_iterator_tag
| ||||
value_type
|
void
| ||||
difference_type
|
| ||||
pointer
|
void
| ||||
reference
|
void
| ||||
container_type
|
Container
|
|
Member types |
(until C++17) |
Member functions
constructs a new back_insert_iterator (public member function) | |
| inserts an object into the associated container (public member function) | |
| no-op (public member function) | |
| no-op (public member function) |
Member objects
| Member name | Definition |
container (protected)
|
a pointer of type Container*
|
Example
Run this code
#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>
int main()
{
std::vector<int> v;
std::generate_n(
std::back_insert_iterator<std::vector<int>>(v),
// Or use std::back_inserter helper
// Or use std::back_insert_iterator(v) C++17's syntax
10,
[n = 0]() mutable { return ++n; }
);
for (int n : v)
std::cout << n << ' ';
std::cout << '\n';
}
Output:
1 2 3 4 5 6 7 8 9 10
See also
| creates a std::back_insert_iterator of type inferred from the argument (function template) | |
| iterator adaptor for insertion at the front of a container (class template) | |
| iterator adaptor for insertion into a container (class template) |