W3cubDocs

/C++

std::set<Key,Compare,Allocator>::clear

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

Erases all elements from the container. After this call, size() returns zero.

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

Parameters

(none).

Return value

(none).

Complexity

Linear in the size of the container, i.e., the number of elements.

Example

#include <algorithm>
#include <iostream>
#include <set>
 
int main()
{
    std::set<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 << "\nSize=" << container.size() << '\n';
 
    std::cout << "Clear\n";
    container.clear();
 
    std::cout << "After clear:";
    std::for_each(container.begin(), container.end(), print);
    std::cout << "\nSize=" << container.size() << '\n';
}

Output:

Before clear: 1 2 3
Size=3
Clear
After clear:
Size=0

Defect reports

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