Section
std::front_insert_iterator
std::front_insert_iterator is a LegacyOutputIterator that prepends elements to a container for which it was constructed. The container’s push_front() member function is called whenever the iterator (whether dereferenced or not) is assigned to. Incrementing the std::front_insert_iterator is a no-op.
# Declarations
template< class Container >
class front_insert_iterator
: public std::iterator<std::output_iterator_tag, void, void, void, void>
(until C++17)
template< class Container >
class front_insert_iterator;
(since C++17)
# Example
#include <algorithm>
#include <deque>
#include <iostream>
#include <iterator>
#include <vector>
namespace stb
{
void println(auto, auto const& d)
{
std::ranges::copy(d, std::ostream_iterator<int>(std::cout, " "));
std::cout << '\n';
}
}
int main()
{
std::vector<int> v{1, 2, 3, 4, 5};
std::deque<int> d;
std::copy(v.begin(), v.end(),
std::front_insert_iterator<std::deque<int>>(d));
// or std::front_inserter(d)
stb::println("{}", d);
}