Index concepts (details)
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.. contents:: Table of Contents
    :local:


.. _concept-details-Index:

Index
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.. cpp:concept:: template <typename Idx> Index

    #. Refines the :cpp:concept:`template <typename T> Integral` concept.

    **Valid Expressions**

    All expressions valid with the following C++ integral types :
        - `bool`
        - `char`
        - `unsigned char`
        - `char16_t`
        - `char32_t`
        - `wchar_t`
        - `unsigned wchar_t`
        - `short`
        - `unsigned short`
        - `int`
        - `unsigned int`
        - `long`
        - `unsigned long`
        - `long long`
        - `unsigned long long`
        - or any implementation-defined extended integer types, including any signed, unsigned, and cv-qualified variants.

    **Possible implementation**

    .. code:: cpp

        template<typename Idx>
        concept Index = Integral<Idx>;