Handling big FP numbers

[Adam D. Ruppe]

On Saturday, 9 February 2019 at 02:12:29 UTC, Murilo wrote:
> prints

Two likely reasons: the D compiler does compile time stuff at 80 
bit, whereas the C++ one probably uses 64 bit, and the D default 
print rounds more aggressively than default C++ printing.

It is useful to put stuff in runtime variables of type `double` 
to avoid the differnt bit stuff, and print with printf in both 
languages to ensure that is the same.