std::deque<T,Allocator>::assign

 

C++

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Named requirements

Feature test macros (C++20)

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Concepts library (C++20)

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Iterators library

Ranges library (C++20)

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Filesystem library (C++17)

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Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

Iterator invalidation

Member function table

Non-member function table

 

std::deque

Member types

Member functions

deque::deque

deque::~deque

deque::operator=

deque::assign

deque::assign_range (C++23)

deque::get_allocator

Element access

deque::at

deque::operator[]

deque::front

deque::back

Iterators

deque::begindeque::cbegin (C++11)

deque::enddeque::cend (C++11)

deque::rbegindeque::crbegin (C++11)

deque::renddeque::crend (C++11)

Capacity

deque::empty

deque::size

deque::max_size

deque::shrink_to_fit (DR*)

Modifiers

deque::clear

deque::insert

deque::insert_range (C++23)

deque::emplace

deque::erase

deque::push_front

deque::emplace_front (C++11)

deque::prepend_range (C++23)

deque::pop_front

deque::push_back

deque::emplace_back (C++11)

deque::append_range (C++23)

deque::pop_back

deque::resize

deque::swap

Non-member functions

std::swap

eraseerase_if (C++20)(C++20)

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

Deduction guides(C++17)

 

void assign( size_type count, const T& value );	(1)
template< class InputIt > void assign( InputIt first, InputIt last );	(2)
void assign( std::initializer_list<T> ilist );	(3)	(since C++11)

Replaces the contents of the container.

1) Replaces the contents with count copies of value value

2) Replaces the contents with copies of those in the range [first, last). The behavior is undefined if either argument is an iterator into *this.

This overload has the same effect as overload (1) if InputIt is an integral type.	(until C++11)
This overload participates in overload resolution only if InputIt satisfies LegacyInputIterator.	(since C++11)

3) Replaces the contents with the elements from the initializer list ilist.

All iterators, pointers and references to the elements of the container are invalidated. The past-the-end iterator is also invalidated.

Parameters

count	-	the new size of the container
value	-	the value to initialize elements of the container with
first, last	-	the range to copy the elements from
ilist	-	initializer list to copy the values from

Complexity

1) Linear in count

2) Linear in distance between first and last

3) Linear in ilist.size()

Example

The following code uses assign to add several characters to a std::deque<char>:

Run this code

#include <deque>
#include <iostream>
#include <string>
 
int main()
{
    std::deque<char> characters;
 
    auto print_deque = [&]()
    {
        for (char c : characters)
            std::cout << c << ' ';
        std::cout << '\n';
    };
 
    characters.assign(5, 'a');
    print_deque();
 
    const std::string extra(6, 'b');
    characters.assign(extra.begin(), extra.end());
    print_deque();
 
    characters.assign({'C', '+', '+', '1', '1'});
    print_deque();
}

Output:

a a a a a
b b b b b b
C + + 1 1

See also

(constructor)

constructs the deque (public member function)