void pop_front();

Removes the first element of the container.

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

#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";
}

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

See also