std::list::clear(3)

💖 NAME 💖

std::list::clear - std::list::clear

Ok bestie, this is the page for std::list::clear(3) from the C++ Standard Libary — yes, that’s the manual name in the header, and we’re keeping it exact. 💅

✨ Synopsis ✨

void clear();  (noexcept since C++11)

This one is iconic: it erases all elements from the container. After this call, size() returns zero. 🫧

It invalidates any references, pointers, and iterators referring to contained elements. Any past-the-end iterator remains valid — that one stays valid, no cap. ✨

🎀 Parameters 🎀

• (none) — literally no arguments, bestie. 🎀

🫶 Return value 🫶

• (none) — it returns nothing; the flex is the deletion. 🫶

🔥 Complexity 🔥

Linear in the size of the container, i.e., the number of elements. So the work scales with how many elements are in there. 🔥

🌈 Example 🌈

// Run this code

#include <iostream>
#include <string_view>
#include <list>

void print_info(std::string_view rem, const std::list<int>& v)
{
    std::cout << rem << "{ ";
    for (const auto& value : v)
        std::cout << value << ' ';
    std::cout << "}\n";
    std::cout << "Size=" << v.size() << '\n';
}

int main()
{
    std::list<int> container{1, 2, 3};
    print_info("Before clear: ", container);
    container.clear();
    print_info("After clear: ", container);
}

🌟 Output 🌟

Before clear: { 1 2 3 }
Size=3
After clear: { }
Size=0

💅 Defect reports 💅

The following behavior-changing defect reports were applied retroactively to previously published C++ standards. 📚

• DR: LWG 2231 — Applied to: C++11 — Behavior as published: complexity guarantee was mistakenly omitted in C++11 — Correct behavior: complexity reaffirmed as linear.

🦋 See also 🦋

• erase — erases elements (public member function)

That’s the whole page, bestie. Source/version: http://cppreference.com · date: 2024.06.10 — mwah 💋✨