std::deque push_front() method

od C++11

// (1) Non const version only
void push_front( const T& value );

// (2) Non const version only
void push_front( T&& value );

do C++11

// (1) Non const version only
void push_front( const T& value );

Prepends the given element value to the beginning of the container

Invalidation

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 - O(1).

Exceptions

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

Example

Main.cpp

#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';
}

Output

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