std::forward_list<T,Allocator>::clear
From cppreference.com
void clear() noexcept;
|
(since C++11) | |
Erases all elements from the container.
Invalidates any references, pointers, and iterators referring to contained elements. Any past-the-end iterator remains valid.
Complexity
Linear in the size of the container, i.e., the number of elements.
Example
Run this code
#include <iostream>
#include <string_view>
#include <forward_list>
void print_info(std::string_view rem, const std::forward_list<int>& v)
{
std::cout << rem << "{ ";
for (const auto& value : v)
std::cout << value << ' ';
std::cout << "}\n";
}
int main()
{
std::forward_list<int> container{1, 2, 3};
print_info("Before clear: ", container);
container.clear();
print_info("After clear: ", container);
}
Output:
Before clear: { 1 2 3 }
After clear: { }
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2231 | C++11 | complexity guarantee was mistakenly omitted in C++11 | complexity reaffirmed as linear |