Is it correct to compare a double to zero if you previously initialized it to zero?

Question

I learnt that comparing a double using == is not a wise practice. However I was wondering if checking if a double has been initialized could be dangerous or not. Fo

Answer 1

In IEEE-754, long story short:

double d;

d = 0.0;
d == 0.0   // guaranteed to evaluate to true, 0.0 can be represented exactly in double

but

double d;

d = 0.1;
d == 0.1   // not guaranteed to evaluate to true