C/C++ floating point issue

I am struggling with a basic floating-point precision
issue. Here is the problem:

double
            d = 0.1;
d += 0.1;
d += 0.1;

d == 0.3 ?
            std::cout << "yes" : std::cout <<
            "no";

Run the code and
you get "no"

I understand that C/C++
store values in binary and that binary storage can not exactly store every value. I also
understand that these small errors compound as you do various math operations on them
(i.e. d += 0.1;).

My questions is if I do need
to test if d == 0.3 (to a reasonable precision.. as is the clear intent of code
above)... how do I do that? I hope the answer is
not:

if (d > 0.2999 &&
            d < 0.3001)
            ...

ALSO.. this
works

float f =
            0.1;
f += 0.1;
f += 0.1;

f == 0.3f ? std::cout
            << "yes" : std::cout <<
            "no";

but I can find
no equivalent "0.3d" in the
language.

Thanks