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

 

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Deduction guides(C++20)

 

constexpr size_type size() const noexcept;		(since C++20)

Returns the number of elements in the span.

Parameters

(none)

Return value

The number of elements in the span.

Note

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

Example

Run this code

#include <iostream>
#include <span>
 
void show_sizes(std::span<const int> span)
{
    std::cout
        << span                 .size() << ' ' // 8
        << span.first(7)        .size() << ' ' // 7
        << span.first<6>()      .size() << ' ' // 6
        << span.last(5)         .size() << ' ' // 5
        << span.last<4>()       .size() << ' ' // 4
        << span.subspan(2, 3)   .size() << ' ' // 3
        << span.subspan<3, 2>() .size() << ' ' // 2
        << '\n';
}
 
int main()
{
    int antique_array[]{1, 2, 3, 4, 5, 6, 7, 8};
    show_sizes(antique_array);
}

Output:

8 7 6 5 4 3 2

See also

(constructor) (C++20)	constructs a span (public member function)
size_bytes (C++20)	returns the size of the sequence in bytes (public member function)