Char is an arithmetic type?

Question

I created a Matrix class, using

static_assert(std::is_arithmetic<T>::value,"");

to check if the template type is an arithmetic type. So I tried with

Matrix<char> matrix1(3,3); // ctor takes number of rows and columns

and it works. The static_assert function is not called with char type. It is normal? char is seen like an arithmetic type?

Answer 1

From the reference:

If T is an arithmetic type (that is, an integral type or a floating-point type), provides the member constant value equal true. For any other type, value is false.

char is an integral type, so the answer is true. The fact that the small integers that fit in a char are often interpreted as codepoints in a particular character encoding space is secondary.

Answer 2

Yes, it's just as a normal integer as any other (int, long, short). That's also a common practice in C(++) to use it for arithmetic, e. g. for converting a digit to its corresponding printable character, you can write

char printable = digit + '0';