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

 

C++

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Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

deque

forward_list (C++11)

list

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set

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map

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unordered_set (C++11)

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unordered_map (C++11)

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stack

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span (C++20)

 

std::deque

Member functions

deque::deque

deque::~deque

deque::operator=

deque::assign

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

Modifiers

deque::clear

deque::insert

deque::emplace

deque::erase

deque::push_front

deque::emplace_front

deque::pop_front

deque::push_back

deque::emplace_back

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 push_front( const T& value );
void push_front( T&& value );		(since C++11)

Prepends the given element value to the beginning of the container.

All iterators, including the past-the-end iterator, are invalidated. No references are invalidated.

Parameters

value

-

the value of the element to prepend

Return value

(none)

Complexity

Constant.

Exceptions

If an exception is thrown, this function has no effect (strong exception guarantee).

Example

Run this code

#include <deque>
#include <iostream>
#include <iomanip>
#include <string>
 
int main()
{
    std::deque<std::string> letters;
 
    letters.push_front("abc");
    std::string s{"def"};
    letters.push_front(std::move(s));
 
    std::cout << "std::deque `letters` holds: ";
    for (auto&& e : letters) std::cout << std::quoted(e) << ' ';
 
    std::cout << "\nMoved-from string `s` holds: " << std::quoted(s) << '\n';
}

Possible output:

std::deque `letters` holds: "def" "abc" 
Moved-from string `s` holds: ""

See also

emplace_front (C++11)	constructs an element in-place at the beginning (public member function)
push_back	adds an element to the end (public member function)
pop_front	removes the first element (public member function)
front_inserter	creates a std::front_insert_iterator of type inferred from the argument (function template)