std::forward_list clear() method

since C++11

// Non const version only
void clear() noexcept;

Erases all elements from the container.

Invalidation

Invalidates any references, or iterators referring to contained elements. Any past-the-end iterators remains valid.

Parameters

(none)

Return value

(none)

Complexity

Linear in the size of the container - O(size()).

Example

Main.cpp

#include <algorithm>
#include <iostream>
#include <forward_list>

int main()
{
    std::forward_list<int> container{1, 2, 3};

    auto print = [](const int& n) { std::cout << " " << n; };

    std::cout << "Before clear:";
    std::for_each(container.begin(), container.end(), print);
    std::cout << '\n';

    std::cout << "Clear\n";
    container.clear();

    std::cout << "After clear:";
    std::for_each(container.begin(), container.end(), print);
    std::cout << '\n';
}

Output

Before clear: 1 2 3
Clear
After clear: