Do classes require explicit constructors?

[Steven Schveighoffer]

On Saturday, 14 February 2026 at 15:42:15 UTC, Brother Bill wrote:

> Is this expected behavior, that is, we always need to create 
> our constructors, no free constructor is built for us by the D 
> compiler?

If you don't define a constructor, a default no-argument 
constructor is provided for you. If you want a constructor with 
parameters, you have to define it.

```d
class C {
   int i;
}

struct S {
   int i;
}

void main() {
   auto c = new C(); //ok
   auto s = new S(); //ok
   auto s2 = new S(1); //ok, default ctor takes optional 
parameters for fields
   auto c2 = new C(1); //error
}
```

> If so, this is a clear departure from C# and Eiffel, where one 
> gets a free constructor if no explicitly declared constructors.

C# also provides the same mechanism as D, a default ctor with no 
args.

-Steve