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Reference

C library:
- <cassert> (assert.h)
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- <cerrno> (errno.h)
- C++11
  <cfenv> (fenv.h)
- <cfloat> (float.h)
- C++11
  <cinttypes> (inttypes.h)
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
- C++11
  <cstdbool> (stdbool.h)
- <cstddef> (stddef.h)
- C++11
  <cstdint> (stdint.h)
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
- C++11
  <ctgmath> (tgmath.h)
- <ctime> (time.h)
- C++11
  <cuchar> (uchar.h)
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
- C++11
  <array>
- <deque>
- C++11
  <forward_list>
- <list>
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- C++11
  <unordered_map>
- C++11
  <unordered_set>
- <vector>
Input/Output:
- <fstream>
- <iomanip>
- <ios>
- <iosfwd>
- <iostream>
- <istream>
- <ostream>
- <sstream>
- <streambuf>
Multi-threading:
- C++11
  <atomic>
- C++11
  <condition_variable>
- C++11
  <future>
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  <mutex>
- C++11
  <thread>
Other:
- <algorithm>
- <bitset>
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  <chrono>
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  <codecvt>
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  <initializer_list>
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  <type_traits>
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  <typeindex>
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- <utility>
- <valarray>

array

C++11
array::array
member functions
- C++11
  array::at
- C++11
  array::back
- C++11
  array::begin
- C++11
  array::cbegin
- C++11
  array::cend
- C++11
  array::crbegin
- C++11
  array::crend
- C++11
  array::data
- C++11
  array::empty
- C++11
  array::end
- C++11
  array::fill
- C++11
  array::front
- C++11
  array::max_size
- C++11
  array::operator[]
- C++11
  array::rbegin
- C++11
  array::rend
- C++11
  array::size
- C++11
  array::swap
non-member overloads
- C++11
  get (array)
- C++11
  relational operators (array)
non-member specializations
- C++11
  tuple_element<array>
- C++11
  tuple_size<array>

public member function

<array>

std::array::size

constexpr size_type size() noexcept;

Return size

Returns the number of elements in the array container.

The size of an array object is always equal to the second template parameter used to instantiate the array template class (N).

Unlike the language operator sizeof, which returns the size in bytes, this member function returns the size of the array in terms of number of elements.

Parameters

none

Return Value

The number of elements contained in the array object.
This is a compile-time constant expression (constexpr).

Member type size_type is an alias of the unsigned integral type size_t.

Example

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

int main ()
{
  std::array<int,5> myints;
  std::cout << "size of myints: " << myints.size() << std::endl;
  std::cout << "sizeof(myints): " << sizeof(myints) << std::endl;

  return 0;
}

Possible output:

size of myints: 5
sizeof(myints): 20

Complexity

Constant.

Iterator validity

No changes.

Data races

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

Exception safety

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

member functions

non-member overloads

non-member specializations