Not if you're calculating the mass defect of an atom nucleus decaying by beta-radiation

Which he isn't doing...

In which case choosing stock float as the data type to use is quite obviously a baaaaaaaaaaaaaaaaaad idea.

True enough.. though a double float would work fine.

A

double only has about 15-17 decimal digits of significant precision. Yes, it's more than a

float, but it all depends on what you're

*doing* with your data. Both

floats and

doubles can approximate 4.014e-31, which isn't the problem (and subsequently, both can approximate 4.014e-31 + 4.014e-31 pretty well). Usually, the problem isn't "Can a

float/

double represent this number?" but instead "Can a

float/

double approximate the mathematical operation between these two (or more) numbers?" Just throwing out a small number doesn't mean that

floats are ruled out; it all depends on what you're doing with that small number.

I'm not saying a

double wouldn't work or that it wouldn't be the better choice in your case. I'm saying it isn't the

*number* that's usually limiting you, it's usually the

*numbers* and what you're

*doing* with the numbers. It's a subtle but significant difference of focus.