Error: function declaration without return type.

[Suliman via Digitalmars-d-learn]

On Tuesday, 6 January 2015 at 21:19:38 UTC, bearophile wrote:
> Suliman:
>
>> 	void foo()
>> 	{
>> 	writeln("test");
>> 	writeln(mystring);
>> 	}
>> 	foo();   <<<<<
>> }
>
> I guess you have to remove that line.
>
> Bye,
> bearophile

Why? I can't call function in instance of class?