C++ sucks

[Peter Korsten]

Martin Naef schreef:

> Peter Korsten wrote:
>> Yes, but here comes the next problem: speed. With C, specifically on 
>> Unix, I can mmap() a file and it magically appears as a bit of memory, 
>> without any effort from my side. Since you need to be jumping through 
>> that memory, you'll be looking at pointers - a concept that Java lacks. 
>> So I'd be looking at C, or C++.
> 
> Let's just hope that data values are properly aligned, unless you're 
> sure your code never runs on anything but x86 CPUs... But yes, it's a 
> nice way of accessing files.

It's actually a Sun SPARC chip on Solaris. On my ageing workstation, 
with a 500 MHz CPU, the program processes almost 5500 records (1.4 MB, I 
think) in a fraction of a second.

>> In C++, you can't have an abstract base class (which for me means 
>> without any private members), implement it in another class, and use 
>> that implementation whilst pretending it's still the interface. In Java, 
> 
> Why not? The only place where you need to know what it is that you're 
> instantiating is the new call. And that's easily hidden using a factory 
> design pattern.

Still a kludge, if you ask me.

>> you can stick that interface in a template class, but my Sun Studio 11 
>> compiler started complaining that it couldn't instantiate a 
>> vector<PetersClass> because PetersClass was abstract.
> 
> Ahh, I see - that's a pecularity of the standard template library in 
> that case. What stops you from using a vector<PeterClass*> instead? This 
> is probably going to be miles more efficient anyway, because a vector of 
>   large classes is rarely efficient. You might also be able to get 
> around that problem by providing your own allocator class.

But I don't want to have to think about these things! :) Java *really* 
is simpler. It just *works*. The run-time compiler is taking care of 
optimising anyway, because it's better at it than I am.

> Oh, and BTW: You're using a feature (template classes) that Java lacks 
> in the first place...

Whilst Java generics are not exactly the same as C++ templates, it's 
quite easy to do something like this:

Map<K extends Enum<K>,V extends List<K>>

which is a one-to-one mapping of one-to-many mappings of a 
yet-to-be-named Enum.

- Peter