std::array (C++11)

In a Nutshell

A fixed-size array that does not decay to a pointer. It delivers the performance of a C-style array while supporting standard container interfaces like size(), iterators, and assignment.

Header

#include <array>

Core API Quick Reference

Operation	Signature	Description
Element access	reference at(size_type pos)	Element access with bounds checking
Element access	reference operator[](size_type pos)	Element access without bounds checking
First element	reference front()	Access the first element
Last element	reference back()	Access the last element
Underlying pointer	T* data() noexcept	Direct access to the underlying array pointer
Fill	void fill(const T& value)	Fill all elements with a specified value
Size	constexpr size_type size() noexcept	Return the number of elements (compile-time constant)
Empty check	constexpr bool empty() noexcept	Check if the array is empty (true when N==0)
Swap	void swap(array& other)	Swap the contents of two arrays
Begin iterator	iterator begin() noexcept	Return an iterator to the beginning

Minimal Example

#include <array>
#include <iostream>
// Standard: C++11
int main() {
    std::array<int, 3> arr = {1, 2, 3};
    arr.fill(0);
    arr[0] = 42;
    for (const auto& v : arr)
        std::cout << v << ' '; // 输出: 42 0 0
    std::cout << "\nsize: " << arr.size(); // 输出: size: 3
}

Embedded Applicability: High

• A zero-overhead abstraction that compiles down to the exact same code as a C-style array, introducing no heap allocation.
• size() is a compile-time constant, making it usable in template metaprogramming and static assertions.
• Supports constexpr, making it ideal for building lookup tables at compile time.
• The built-in bounds checking of at() simplifies debugging, and it can be removed in Release builds.

Compiler Support

GCC	Clang	MSVC
4.4	3.1	19.0

See Also

• Tutorial: std::array In Depth
• cppreference: std::array

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