Why std::complex is not an arithmetic type?

Question

I created the following Matrix class: ``` template class Matrix { static_assert(std::is_arithmetic::value,""); public: Matrix(size_t n_rows, size_t n_cols); Matrix(size_t n_rows, size_t n_cols, const T& value); void fill(const T& value); size_t n_rows() const; size_t n_cols() const; void print(std::ostream& out) const; T& operator()(size_t row_index, size_t col_index); T operator()(size_t row_index, size_t col_index) const; bool operator==(const Matrix& matrix) const; bool operator!=(const Matrix& matrix) const; Matrix& operator+=(const Matrix& matrix); Matrix& operator-=(const Matrix& matrix); Matrix operator+(const Matrix& matrix) const; Matrix operator-(const Matrix& matrix) const; Matrix& operator*=(const T& value); Matrix& operator*=(const Matrix& matrix); Matrix operator*(const Matrix& matrix) const; private: size_t rows; size_t cols; std::vector data; }; ``` I tried to use a matrix of std::complex: ``` Matrix

Accepted Answer

The `arithmetic` in `is_arithmetic` is a misnomer. Or rather, it's a C++-nomer. It doesn't mean the same thing as it means in English. It just means it's one of the built-in numeric types(int, float, etc...). `std::complex` is not a built-in, it is a class.

Do you really need that `static_assert`? Why not just let the user try it with any type? If the type doesn't support the needed operations, then tough luck.

Why std::complex is not an arithmetic type?

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