std::vector<T,Allocator>::insert
(1) | ||
iterator insert( iterator pos, const T& value ); | (until C++11) | |
iterator insert( const_iterator pos, const T& value ); | (since C++11) | |
iterator insert( const_iterator pos, T&& value ); | (2) | (since C++11) |
(3) | ||
void insert( iterator pos, size_type count, const T& value ); | (until C++11) | |
iterator insert( const_iterator pos, size_type count, const T& value ); | (since C++11) | |
(4) | ||
template< class InputIt > void insert( iterator pos, InputIt first, InputIt last); | (until C++11) | |
template< class InputIt > iterator insert( const_iterator pos, InputIt first, InputIt last ); | (since C++11) | |
iterator insert( const_iterator pos, std::initializer_list<T> ilist ); | (5) | (since C++11) |
Inserts elements at the specified location in the container.
1-2) inserts
value
before pos
3) inserts
count
copies of the value
before pos
4) inserts elements from range
The behavior is undefined if
[first, last)
before pos
. This overload has the same effect as overload (3) if InputIt is an integral type. | (until C++11) |
This overload only participates in overload resolution if InputIt qualifies as LegacyInputIterator, to avoid ambiguity with the overload (3). | (since C++11) |
first
and last
are iterators into *this
.
5) inserts elements from initializer list
ilist
before pos
.Causes reallocation if the new size()
is greater than the old capacity()
. If the new size()
is greater than capacity()
, all iterators and references are invalidated. Otherwise, only the iterators and references before the insertion point remain valid. The past-the-end iterator is also invalidated.
Parameters
pos | - | iterator before which the content will be inserted. pos may be the end() iterator |
value | - | element value to insert |
first, last | - | the range of elements to insert, can't be iterators into container for which insert is called |
ilist | - | initializer list to insert the values from |
Type requirements | ||
-T must meet the requirements of CopyAssignable and CopyInsertable in order to use overload (1). |
||
-T must meet the requirements of MoveAssignable and MoveInsertable in order to use overload (2). |
||
-T must meet the requirements of CopyAssignable and CopyInsertable in order to use overload (3). |
||
-T must meet the requirements of EmplaceConstructible in order to use overload (4,5). |
||
-T must meet the requirements of MoveAssignable and MoveInsertable in order to use overload (4). required only if InputIt satisfies LegacyInputIterator but not LegacyForwardIterator. (until C++17) |
||
-T must meet the requirements of Swappable, MoveAssignable, MoveConstructible and MoveInsertable in order to use overload (4,5). (since C++17) |
Return value
1-2) Iterator pointing to the inserted
value
3) Iterator pointing to the first element inserted, or
pos
if count==0
.
4) Iterator pointing to the first element inserted, or
pos
if first==last
.
5) Iterator pointing to the first element inserted, or
pos
if ilist
is empty.Complexity
1-2) Constant plus linear in the distance between
pos
and end of the container.
3) Linear in
count
plus linear in the distance between pos
and end of the container.
4) Linear in
std::distance(first, last)
plus linear in the distance between pos
and end of the container.
5) Linear in
ilist.size()
plus linear in the distance between pos
and end of the container.Exceptions
If an exception is thrown when inserting a single element at the end, and T is CopyInsertable or std::is_nothrow_move_constructible<T>::value
is true
, there are no effects (strong exception guarantee).
Example
#include <iostream> #include <vector> void print_vec(const std::vector<int>& vec) { for (auto x: vec) { std::cout << ' ' << x; } std::cout << '\n'; } int main () { std::vector<int> vec(3,100); print_vec(vec); auto it = vec.begin(); it = vec.insert(it, 200); print_vec(vec); vec.insert(it,2,300); print_vec(vec); // "it" no longer valid, get a new one: it = vec.begin(); std::vector<int> vec2(2,400); vec.insert(it+2, vec2.begin(), vec2.end()); print_vec(vec); int arr[] = { 501,502,503 }; vec.insert(vec.begin(), arr, arr+3); print_vec(vec); }
Output:
100 100 100 200 100 100 100 300 300 200 100 100 100 300 300 400 400 200 100 100 100 501 502 503 300 300 400 400 200 100 100 100
See also
(C++11) | constructs element in-place (public member function) |
adds an element to the end (public member function) |
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