public member function
<unordered_set>

std::unordered_set::clear

void clear() noexcept;
Clear content
All the elements in the unordered_set container are dropped: their destructors are called, and they are removed from the container, leaving it with a size of 0.

Parameters

none

Return value

none

Example

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// clearing unordered_set
#include <iostream>
#include <string>
#include <unordered_set>

int main ()
{
  std::unordered_set<std::string> myset =
    { "chair", "table", "lamp", "sofa" };

  std::cout << "myset contains:";
  for (const std::string& x: myset) std::cout << " " << x;
  std::cout << std::endl;

  myset.clear();
  myset.insert("bed");
  myset.insert("wardrobe");
  myset.insert("nightstand");

  std::cout << "myset contains:";
  for (const std::string& x: myset) std::cout << " " << x;
  std::cout << std::endl;

  return 0;
}


Possible output:
myset contains: sofa lamp table chair
myset contains: nightstand wardrobe bed

Complexity

Linear on size (destructors).

Iterator validity

All iterators, pointers and references are invalidated.

See also

  • 9316991614 2018-02-25
  • 191841613 2018-02-25
  • 16411612 2018-02-25
  • 6081981611 2018-02-25
  • 1784561610 2018-02-25
  • 4651609 2018-02-25
  • 9348111608 2018-02-25
  • 2513771607 2018-02-25
  • 6478461606 2018-02-24
  • 4985791605 2018-02-24
  • 5637141604 2018-02-24
  • 282181603 2018-02-24
  • 6217941602 2018-02-24
  • 5076141601 2018-02-24
  • 714281600 2018-02-24
  • 6607141599 2018-02-24
  • 949041598 2018-02-24
  • 6809961597 2018-02-24
  • 671871596 2018-02-24
  • 7107821595 2018-02-24