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

    From cppreference.com
     
    C++
     
    Containers library
     
    std::span
     
    constexpr reference back() const;
    		(since C++20)

    Returns a reference to the last element in the span.

    If empty() is true, the behavior is undefined.

    		(until C++26)

    If empty() is true:

    		(since C++26)

    Return value

    A reference to the back element.

    Complexity

    Constant.

    Notes

    For a span c, the expression c.back() is equivalent to *(c.end() - 1).

    Example

    Run this code
    #include <iostream>
#include <span>

void print_forward(const std::span<const int> span)
{
    for (auto n{span.size()}; n != 0; --n)
        std::cout << span.last(n).front() << ' ';
    std::cout << '\n';
}

void print_backward(const std::span<const int> span)
{
    for (auto n{span.size()}; n != 0; --n)
        std::cout << span.first(n).back() << ' ';
    std::cout << '\n';
}

int main()
{
    constexpr int numbers[]{0, 1, 2, 3, 4};
    print_forward(numbers);
    print_backward(numbers);
}

    Output: 

    0 1 2 3 4
4 3 2 1 0

    See also

    		 access the first element
    (public member function) [edit]