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

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< cpp‎ | container‎ | span

template< std::size_t Count > constexpr std::span<element_type, Count> last() const; | (1) | (since C++20)
constexpr std::span<element_type, std::dynamic_extent> last( size_type Count ) const; | (2) | (since C++20)

Obtains a span that is a view over the last Count elements of this span. The program is ill-formed if Count > Extent. The behavior is undefined if Count > size().

### Return value

A span `r` that is a view over the last Count elements of *this, such that r.data() == this->data() + (this->size() - Count) && r.size() == Count.

### Example

Run this code

    #include <iostream>
    #include <span>
    #include <string_view>

    auto print = [](std::string_view const title, auto const& container)
    {
        std::cout << title << "[" << std::size(container) << "]{ ";
        for (auto const& elem : container)
            std::cout << elem << ", ";
        std::cout << "};\n";
    };

    void run(std::span<const int> span)
    {
        print("span: ", span);

        std::span<const int, 3> span_last = span.last<3>();
        print("span.last<3>(): ", span_last);

        std::span<const int, std::dynamic_extent> span_last_dynamic = span.last(2);
        print("span.last(2):   ", span_last_dynamic);
    }

    int main()
    {
        int a[8]{ 1, 2, 3, 4, 5, 6, 7, 8, };
        print("int  a", a);
        run(a);
    }

Output:

    int  a[8]{ 1, 2, 3, 4, 5, 6, 7, 8, };
    span: [8]{ 1, 2, 3, 4, 5, 6, 7, 8, };
    span.last<3>(): [3]{ 6, 7, 8, };
    span.last(2):   [2]{ 7, 8, };

### See also

first (C++20) | obtains a subspan consisting of the first N elements of the sequence (public member function)
subspan (C++20) | obtains a subspan (public member function)

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