Method begin

tests/mathreference.h:54–54

    Array() : size_(0), data_(nullptr) {}
    Array(size_t s, const T *p) : size_(s), data_(p) {}
    const T *begin() const { return data_; }
    const T *end() const { return data_ + size_; }
    std::size_t size() const { return size_; }
};