Comment by Aardwolf

C++ hex floats are an interesting combination of 3 numeric bases in one!

the mantissa is written in base 16

the exponent is written in base 10

the exponent itself is a power of 2 (not of 16 or 2), so that's base 2

One can only wonder how that came to be. I think they chose base 10 for the exponent to allow using the 'f' suffix to denote float (as opposed to double)