Difference between revisions of "cpp/container/set/clear"
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Latest revision as of 18:39, 20 November 2021
| void clear(); |
(noexcept since C++11) | |
Erases all elements from the container. After this call, size() returns zero.
Invalidates any references, pointers, and iterators referring to contained elements. Any past-the-end iterator remains valid.
Contents |
[edit] Parameters
(none)
[edit] Return value
(none)
[edit] Complexity
Linear in the size of the container, i.e., the number of elements.
[edit] Example
Run this code
#include <iostream> #include <string_view> #include <set> void print_info(std::string_view rem, const std::set<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::set<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=0Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 224 | C++98 | the complexity was log(size()) + N, but N was not defined | corrected to 'linear in size()' |
[edit] See also
| erases elements (public member function) |
