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std::span<T,Extent>:: size

From cppreference.net
C++
Containers library
std::span
constexpr size_type size ( ) const noexcept ;
(since C++20)

Returns the number of elements in the span.

Contents

Return value

The number of elements in the span.

Note

Feature-test macro Value Std Feature
__cpp_lib_ssize 201902L (C++20) std::ssize and unsigned std::span::size

Example

Run this code 
#include <span>
int main()
{
    constexpr static int c_array[]{1, 2, 3, 4, 5, 6, 7, 8};
    constexpr std::span<const int> span{c_array};
    static_assert(8 == span.size());
    static_assert(7 == span.first(7).size());
    static_assert(6 == span.first<6>().size());
    static_assert(5 == span.last(5).size());
    static_assert(4 == span.last<4>().size());
    static_assert(3 == span.subspan(2, 3).size());
    static_assert(2 == span.subspan<3, 2>().size());
    static_assert(1 == span.subspan<7>().size());
}

See also

constructs a span
(public member function)
returns the size of the sequence in bytes
(public member function)