std::span<T,Extent>::back
| constexpr reference back() const; | 
Returns a reference to the last element in the span.
Calling back on an empty span results in undefined behavior.
Parameters
(none).
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
See also
| access the first element (public member function) | 
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