Unsigned double in C++?

Question

Hello everyone,

Why doesn't C++ support unsigned double syntax?

Thanks in advance

Answer 1

Because typical floating point formats don't support unsigned numbers. See, for instance, this list of IEEE 754 formats.

Adding a numerical format that isn't supported by common hardware just makes life difficult for compiler writers, and is probably not considered worth the effort.

Answer 2

Because most floating point hardware doesn't support unsigned types. Some graphics cards do work with unsigned floating point, but it's generally internal, not really visible to a program or user.

Answer 3

Unsigned integers gain an extra bit of precision and have slightly different bit-wise semantics to signed integers. Floats and doubles always reserve a bit for the sign (on most hardware) and have no bit-wise semantics, so there's no real benefit in having an unsigned real type.