concept_play.cpp

#include <concepts>

template <typename T> concept CPLEXArrayLite = requires(T o)
{
    {
        o.getEnv()
    }
    ->std::same_as<int>;
    {
        o.getSize()
    }
    ->std::convertible_to<int>;
    o[std::declval<int>()];
};


template <typename T>
concept Array = requires(T a)
{
    typename T::value_type;
    {a.operator[](std::declval<int>())}
    -> std::convertible_to<typename T::value_type>;
    {a.size()}
    -> std::convertible_to<std::size_t>;
};

#include <vector>
#include <array>

static_assert(Array<std::vector<int>>);

static_assert(Array<std::array<int, 10>>);