On Saturday, 21 October 2017 at 20:17:12 UTC, NX wrote:
I was working on some sort of math library for use in graphical
computing and I wrote something like this:
const float PiOver2 = (atan(1.0) * 4) / 2;
Interestingly enough, I realized that atan() returns double (in
this case) but wait, it's assigned to a float variable!
Compiler didn't even emit warnings, let alone errors.
I see no reason as to why would this be legal in this century,
especially in D.
So can someone tell me what's the argument against this?
Why type conversions differ between integral and floating types?
Why can't I assign a long to an int but it's fine when
assigning double to float?
I think this is a serious topic and needs clarification.
D is compliant with C++ in this case (see
http://en.cppreference.com/w/cpp/language/implicit_conversion) so
the question is rather why does C++ allow this conversion. When
you convert a double to a float you're more likely to have a
precision loss while when you convert an ulong to an int you risk
a most serious data loss.
