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

 

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void push_front( const T& value );	(1)
void push_front( T&& value );	(2)	(since C++11)

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

All iterators (including 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 for any reason, these functions have no effect (strong exception safety guarantee).

Example

Run this code

#include <deque>
#include <iomanip>
#include <iostream>
#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)