C++

Reference

<set>

set

public member function
<set>

std::set::size

size_type size() const;
size_type size() const noexcept;
Return container size
Returns the number of elements in the set container.

Parameters

none

Return Value

The number of elements in the container.

Member type size_type is an unsigned integral type.

Example

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// set::size
#include <iostream>
#include <set>

int main ()
{
  std::set<int> myints;
  std::cout << "0. size: " << myints.size() << '\n';

  for (int i=0; i<10; ++i) myints.insert(i);
  std::cout << "1. size: " << myints.size() << '\n';

  myints.insert (100);
  std::cout << "2. size: " << myints.size() << '\n';

  myints.erase(5);
  std::cout << "3. size: " << myints.size() << '\n';

  return 0;
}

Output:
0. size: 0
1. size: 10
2. size: 11
3. size: 10


Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed.
Concurrently accessing the elements of a set is safe.

Exception safety

No-throw guarantee: this member function never throws exceptions.

See also

set::max_size
Return maximum size (public member function)
set::empty
Test whether container is empty (public member function)