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

From cppreference.com
< cpp‎ | container‎ | span

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)

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