C++

Reference

<deque>

deque

public member function
<deque>

std::deque::size

size_type size() const;
size_type size() const noexcept;
Return size
Returns the number of elements in the deque 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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// deque::size
#include <iostream>
#include <deque>

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

  for (int i=0; i<5; i++) myints.push_back(i);
  std::cout << "1. size: " << myints.size() << '\n';

  myints.insert (myints.begin(),5,100);
  std::cout << "2. size: " << myints.size() << '\n';

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

  return 0;
}

Output:
0. size: 0
1. size: 5
2. size: 10
3. size: 9


Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed.
No contained elements are accessed: concurrently accessing or modifying them is safe.

Exception safety

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

See also

deque::empty
Test whether container is empty (public member function)
deque::resize
Change size (public member function)
deque::max_size
Return maximum size (public member function)