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

 

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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
operator==operator<=> (C++20) swap(std::deque) erase(std::deque)erase_if(std::deque) (C++20)(C++20)	operator!=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
Deduction guides(C++17)

 

void pop_front();

Removes the first element of the container.

If empty() is true, the behavior is undefined.	(until C++26)
If empty() is true: If the implementation is hardened, a contract violation occurs. If the implementation is not hardened, the behavior is undefined.	(since C++26)

Iterators and references to the erased element are invalidated. If the element is the last element in the container, the end() iterator is also invalidated. Other references and iterators are not affected.

Complexity

Constant.

Example

Run this code

#include <deque>
#include <iostream>

int main()
{
    std::deque<char> chars{'A', 'B', 'C', 'D'};
    
    for (; !chars.empty(); chars.pop_front())
        std::cout << "chars.front(): '" << chars.front() << "'\n";
}

Output:

chars.front(): 'A'
chars.front(): 'B'
chars.front(): 'C'
chars.front(): 'D'

See also

pop_back	removes the last element (public member function)
push_front	inserts an element to the beginning (public member function)
front	access the first element (public member function)