Is this normal or a bug ?

[claptrap]

On Monday, 3 July 2023 at 08:24:22 UTC, Mehdi wrote:
> Hello, d community! I am currently exploring the possibilities 
> of interoperability between C++ and D. While conducting some 
> tests, I came across an interesting case. Here is the C++ code

import std.stdio;

void main()
{
     writefln ("%.15f", 10.1 + 20.6);
     writefln ("%.15f", 10.1f + 20.6f);
}

prints this...

30.699999999999999
30.700000762939453

the problem is..

assert(10.1 + 20.6 == float_test(10.1, 20.6));

10.1 + 20.6 is done with double (or maybe extended on DMD) 
precision
float_test(10.1, 20.6) is done with float precision