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date: Thu, 17 Jul 2008 17:34:15 -0500,
group: microsoft.public.dotnet.languages.csharp
back
Re: how does C# compare to C++ and VB
On Thu, 17 Jul 2008 15:34:15 -0700, Daniel wrote:
> If I'm reasonably familiar with C++ and am an expert at Visual Basic,
> what
> principles should I apply in order to understand C# so that I could more
> quickly learn the language?
How did you get reasonably familiar with C++ without making a substantial
investment in it?
Seriously though, I think you're overthinking things. C#, C++, and VB all
have substantially the same kinds of features. They are more like each
other (especially C++ and C#) than they are like most other languages.
Each language has some specific differences, and some people will swear
one is broadly superior to another, but on the whole -- and especially in
the context of .NET programming -- it really just comes down to your
preferences.
I strongly prefer C# over VB and C++, at least for .NET programming, and I
have my reasons for that. But I don't think I've written any C# programs
that couldn't have been written in either of the other languages, and
80-90% of the code would have been pretty much the same even.
As for how best to learn C#, I'd say that using it is the best way to
learn it. There are threads in this newsgroup with recommendations for
specific books, and if that's a learning technique that's useful to you,
you should check those out too.
Other than that, I can't imagine what "principles" you would "apply" to
"more quickly" learn C#. As they say, "just do it". :)
Pete
date: Thu, 17 Jul 2008 15:46:28 -0700
author: Peter Duniho
Re: how does C# compare to C++ and VB
Peter Duniho wrote:
> On Thu, 17 Jul 2008 15:34:15 -0700, Daniel
> wrote:
>> If I'm reasonably familiar with C++ and am an expert at Visual Basic,
>> what
>> principles should I apply in order to understand C# so that I could
>> more quickly learn the language?
>
> How did you get reasonably familiar with C++ without making a
> substantial investment in it?
>
> Seriously though, I think you're overthinking things. C#, C++, and
> VB all have substantially the same kinds of features. They are more
> like each other (especially C++ and C#) than they are like most other
> languages. Each language has some specific differences, and some
C# is far closer to Java and VB.NET than it is to C++. C++ has
substantially the same OOP features as C#, but templates can do a not of
things generics can't, other features are more powerful as well, and as a
result C++ supports modern non-OOP programming styles (TMP for example).
> people will swear one is broadly superior to another, but on the
> whole -- and especially in the context of .NET programming -- it
> really just comes down to your preferences.
>
> I strongly prefer C# over VB and C++, at least for .NET programming,
> and I have my reasons for that. But I don't think I've written any
> C# programs that couldn't have been written in either of the other
> languages, and 80-90% of the code would have been pretty much the
> same even.
I agree with this. Writing .NET code with C++/CLI is really sluggish
compared to C#, at least once you add in the Visual Studio environment and
add-ins like Resharper/Refactor Pro/VAX. Making tools for C# is just much
much easier than doing the same for C++.
date: Fri, 18 Jul 2008 09:03:37 -0500
author: Ben Voigt [C++ MVP] am
Re: how does C# compare to C++ and VB
On Fri, 18 Jul 2008 07:03:37 -0700, Ben Voigt [C++ MVP]
<rbv@nospam.nospam> wrote:
> [...]
>> Seriously though, I think you're overthinking things. C#, C++, and
>> VB all have substantially the same kinds of features. They are more
>> like each other (especially C++ and C#) than they are like most other
>> languages. Each language has some specific differences, and some
>
> C# is far closer to Java and VB.NET than it is to C++.
I agree whole-heartedly about being closer to Java. But the OP didn't ask
about Java. :)
I disagree on the VB/VB.NET point, but I guess that's a matter of opinion
so not entirely unexpected. In spite of some fundamental conceptual
differences between C++ and C#, I find moving back and forth between those
languages much easier than moving back and forth between C# and VB.NET and
so to me they are more similar to each other than C# is to VB.NET (and
this is especially true if only limiting the comparison to C++/CLI rather
than C++ more generally).
> C++ has
> substantially the same OOP features as C#, but templates can do a not of
> things generics can't,
And generics can do things templates can't. They are similar, but not
equivalent.
> other features are more powerful as well, and as a
> result C++ supports modern non-OOP programming styles (TMP for example).
IMHO it's inflammatory to describe one language as "more powerful" as
compared to another, and in most cases (including this one) decidedly
inaccurate.
Of course, if by "other features are more powerful" you did not mean to
imply that C# does not also have "more powerful" features, then my concern
is misplaced. But that's not how I read your statement.
Pete
date: Fri, 18 Jul 2008 09:53:04 -0700
author: Peter Duniho
Re: how does C# compare to C++ and VB
Peter Duniho wrote:
> On Fri, 18 Jul 2008 07:03:37 -0700, Ben Voigt [C++ MVP]
> <rbv@nospam.nospam> wrote:
>
>> [...]
>>> Seriously though, I think you're overthinking things. C#, C++, and
>>> VB all have substantially the same kinds of features. They are more
>>> like each other (especially C++ and C#) than they are like most
>>> other languages. Each language has some specific differences, and
>>> some
>>
>> C# is far closer to Java and VB.NET than it is to C++.
>
> I agree whole-heartedly about being closer to Java. But the OP
> didn't ask about Java. :)
>
> I disagree on the VB/VB.NET point, but I guess that's a matter of
> opinion so not entirely unexpected. In spite of some fundamental
They don't "look" alike, but the actual feature matrices for VB.NET and C#
are almost identical. VB has exception filters that C# doesn't. I suspect
we'd be hard-pressed to list more than 6 more differences.
> conceptual differences between C++ and C#, I find moving back and
> forth between those languages much easier than moving back and forth
> between C# and VB.NET and so to me they are more similar to each
> other than C# is to VB.NET (and this is especially true if only
> limiting the comparison to C++/CLI rather than C++ more generally).
>
>> C++ has
>> substantially the same OOP features as C#, but templates can do a
>> not of things generics can't,
>
> And generics can do things templates can't. They are similar, but not
> equivalent.
Generics can do things that the Microsoft C++ compiler can't do with
templates, because Microsoft C++ doesn't support the C++ standard
(specifically export). Since I'm aware of only one C++ compiler that does
implement export, your statement is correct for all practical purposes.
However, the Microsoft C++ compiler does support generics.
>
>> other features are more powerful as well, and as a
>> result C++ supports modern non-OOP programming styles (TMP for
>> example).
>
> IMHO it's inflammatory to describe one language as "more powerful" as
> compared to another, and in most cases (including this one) decidedly
> inaccurate.
Would you disagree that C++ is more powerful than C? It's practically a
100% superset. The same is true of C++ vs C#, although they're a lot closer
in capability. Actually one of the big points in favor of C# is that it's
controlled by a single company, so new features reach developers a lot more
often, in many cases earlier. C++03 beats C# 1.x which was available at the
same time. And C++0x will be a near superset of whatever version of C# is
out at the same time, probably 4.x
>
> Of course, if by "other features are more powerful" you did not mean
> to imply that C# does not also have "more powerful" features, then my
> concern is misplaced. But that's not how I read your statement.
C# has some of these powerful features that don't have a direct equivalent
in C++. There's some very nice syntactic sugar, like anonymous methods
(although closures are coming soon to C++ as well). But none of them
respresent a truely different paradigm, such as TMP is, so ultimately most
of the reasons to choose C# over C++ (such as garbage collection, runtime
code generation, etc) come from either lack of features (making the language
easier to learn) or the CLR, which isn't a feature of any particular .NET
language. These can be accomplished in C++ by using an appropriate library
and runtime, one of which, thanks to the /clr option, is .NET itself.
>
> Pete
date: Fri, 18 Jul 2008 14:26:32 -0500
author: Ben Voigt [C++ MVP] am
Re: how does C# compare to C++ and VB
On Fri, 18 Jul 2008 12:34:14 -0700, Jon Skeet [C# MVP]
wrote:
> [...]
> That's 6 - can anyone add to it to go to *more* than 6?
Sure, I think there's at least a couple of obvious ones:
-- VB has a concept of a "default instance". That is, if you refer to
a type by name rather than an explicitly allocated instance, VB creates
the instance for you. I don't know VB well enough to know if that's a
language feature or something special to the Form class, but it's
certainly something that happens in VB but not in C#.
-- The "With" statement.
-- VB's support for declaring an event handler that specifies what
event it's actually handling (in C# you have to subscribe the event
explicitly).
Oops, sorry. That's three.
I suspect an expert in both languages could come up with a great deal many
more than that.
That said, I don't really disagree with the overall idea that VB.NET and
C# share a great number of features. That's not surprising given that
they are specifically designed to target the same run-time and framework.
What does surprise me is that Ben can on the one hand argue that VB.NET
and C# are closer to each other than C# is to C++, and yet on the other
hand argue that C++ is essentially a "superset" of C#. At best, C++ can
only be thought of as a superset of C++ if one looks only at the Microsoft
C++/CLI implementation of C++ (reasoning that I find a bit disingenuous),
but even if one does, the implication of that assumption is that C++ is
just as similar to VB.NET as C# is.
But as I've said before, personally I find all three languages
functionally to be basically equivalent. This entire discussion is
starting to smack of "my langauge is better than yours" and I think that's
a silly discussion to have. Religious arguments of that nature don't
interest me much.
Pete
date: Fri, 18 Jul 2008 13:03:04 -0700
author: Peter Duniho
Re: how does C# compare to C++ and VB
Peter Duniho wrote:
> On Fri, 18 Jul 2008 12:34:14 -0700, Jon Skeet [C# MVP]
> wrote:
>
>> [...]
>> That's 6 - can anyone add to it to go to *more* than 6?
>
> Sure, I think there's at least a couple of obvious ones:
>
> -- VB has a concept of a "default instance". That is, if you
> refer to a type by name rather than an explicitly allocated instance,
> VB creates the instance for you. I don't know VB well enough to know
> if that's a language feature or something special to the Form class,
> but it's certainly something that happens in VB but not in C#.
>
> -- The "With" statement.
>
> -- VB's support for declaring an event handler that specifies what
> event it's actually handling (in C# you have to subscribe the event
> explicitly).
>
> Oops, sorry. That's three.
These seem to me to be more syntactic than anything, unlike the ones Jon
came up with, which for the most part cannot be duplicated in the other
language at all.
[snip]
>
> What does surprise me is that Ben can on the one hand argue that
> VB.NET and C# are closer to each other than C# is to C++, and yet on
> the other hand argue that C++ is essentially a "superset" of C#. At
> best, C++ can only be thought of as a superset of C++ if one looks
> only at the Microsoft C++/CLI implementation of C++ (reasoning that I
> find a bit disingenuous), but even if one does, the implication of
> that assumption is that C++ is just as similar to VB.NET as C# is.
Let's use "natural numbers", "cardinal numbers", and "real numbers". Would
you dispute that "natural numbers" are most similar to "cardinal numbers",
but "real numbers" are a superset of both?
Similarly, C++ is an almost 100% superset of C89, yet C89 and C99 are far
closer to each other in every respect than to C++.
>
> But as I've said before, personally I find all three languages
> functionally to be basically equivalent. This entire discussion is
> starting to smack of "my langauge is better than yours" and I think
> that's a silly discussion to have. Religious arguments of that
> nature don't interest me much.
I'd suggest you read some of Stroustrup's papers to understand just how far
beyond simple OOP C++ can go. Yes, if you restrict yourself to thinking of
the approach you'd take with C#, then all three are basically equivalent.
But C++ enables other approaches entirely that C# and VB have no way to
represent.
>
> Pete
date: Fri, 18 Jul 2008 16:24:38 -0500
author: Ben Voigt [C++ MVP] am
Re: how does C# compare to C++ and VB
On Fri, 18 Jul 2008 14:24:38 -0700, Ben Voigt [C++ MVP]
<rbv@nospam.nospam> wrote:
> [...]
>> Oops, sorry. That's three.
>
> These seem to me to be more syntactic than anything, unlike the ones Jon
> came up with, which for the most part cannot be duplicated in the other
> language at all.
On "With" I see your point (though I'm not sure why it's relevant...it's
still a real difference between the languages). On the other two, I don't
see those as any more "simply syntactic" than for example VB's lack of
multi-statement lamba's (which are at least partially duplicated simply by
putting the code in a separate method, just as anonymous methods
themselves don't do anything you couldn't write explicitly if you wanted
to), or iterator blocks (again, it's just "compiler magic"...you could
implement the same functionality more explicitly in VB.NET if you like,
just without any help from the compiler).
> Let's use "natural numbers", "cardinal numbers", and "real numbers".
> Would
> you dispute that "natural numbers" are most similar to "cardinal
> numbers",
> but "real numbers" are a superset of both?
Forgive me if I fail to see the point of the analogy. The "superset" and
"subset" relationship mathematics between the kinds of numbers you
describe is well-defined. Not so with computer languages, nor the idea of
"similar".
The problem here is (I believe) is a fundamental difference in the way we
perceive the concepts of "similar".
> [...]
> I'd suggest you read some of Stroustrup's papers to understand just how
> far
> beyond simple OOP C++ can go. Yes, if you restrict yourself to thinking
> of
> the approach you'd take with C#, then all three are basically equivalent.
> But C++ enables other approaches entirely that C# and VB have no way to
> represent.
Why not provide an example? I'm not going to go off picking to read
random writings by the designer of C++ in the hopes of figuring out what
you mean. If you think there's such a clear difference, it should not be
difficult to present a practical example clearly demonstrating how C++ is
"more powerful" in a way that C# cannot be.
Personally, the thing I find "most powerful" about C# is its integration
with .NET. Yes, you can write .NET code in C++. But it's clumsy, and
frankly I don't feel that features in C++ that aren't available in C#
justify dealing with the clumsiness. The relative frequency with which
the opposing issues come up is heavily weighted in favor of C#, at least
in my own experience.
Others may have different experiences and thus different conclusions. But
I don't think that justifies a claim of one language being "more powerful"
than others. Indeed, that sort of claim just leads to pointless, endless
debates about "my language is better than yours", which as I've mentioned
I find completely valueless.
Pete
date: Fri, 18 Jul 2008 14:45:37 -0700
author: Peter Duniho
Re: how does C# compare to C++ and VB
Peter Duniho wrote:
> On Fri, 18 Jul 2008 14:24:38 -0700, Ben Voigt [C++ MVP]
> <rbv@nospam.nospam> wrote:
>
>> [...]
>>> Oops, sorry. That's three.
>>
>> These seem to me to be more syntactic than anything, unlike the ones
>> Jon came up with, which for the most part cannot be duplicated in
>> the other language at all.
>
> On "With" I see your point (though I'm not sure why it's
> relevant...it's still a real difference between the languages). On
> the other two, I don't see those as any more "simply syntactic" than
> for example VB's lack of multi-statement lamba's (which are at least
> partially duplicated simply by putting the code in a separate method,
> just as anonymous methods themselves don't do anything you couldn't
> write explicitly if you wanted to), or iterator blocks (again, it's
Ahh, but lambda's can be traversed as a parse tree instead of turned into a
delegate. The workaround of putting the code in a separate method doesn't
support that.
> just "compiler magic"...you could implement the same functionality
> more explicitly in VB.NET if you like, just without any help from the
> compiler).
>> Let's use "natural numbers", "cardinal numbers", and "real numbers".
>> Would
>> you dispute that "natural numbers" are most similar to "cardinal
>> numbers",
>> but "real numbers" are a superset of both?
>
> Forgive me if I fail to see the point of the analogy. The "superset"
> and "subset" relationship mathematics between the kinds of numbers you
> describe is well-defined. Not so with computer languages, nor the
> idea of "similar".
So you snipped the (self-evident) example using computer languages. In any
case, "superset" does not imply "similar".
>
> The problem here is (I believe) is a fundamental difference in the
> way we perceive the concepts of "similar".
>
>> [...]
>> I'd suggest you read some of Stroustrup's papers to understand just
>> how far
>> beyond simple OOP C++ can go. Yes, if you restrict yourself to
>> thinking of
>> the approach you'd take with C#, then all three are basically
>> equivalent. But C++ enables other approaches entirely that C# and VB
>> have no way to represent.
>
> Why not provide an example? I'm not going to go off picking to read
> random writings by the designer of C++ in the hopes of figuring out
> what you mean. If you think there's such a clear difference, it
> should not be difficult to present a practical example clearly
> demonstrating how C++ is "more powerful" in a way that C# cannot be.
Well, there are quite a few examples here:
http://www.codeproject.com/KB/cpp/crc_meta.aspx
But a simple one you should be very familiar with is
EqualityComparer::Default
Just you try to make a Dictionary in .NET that supports *any* Key class or
struct without a virtual call to test equality. I suspect that the .NET JIT
is coded to specifically recognize Dictionary or at least
EqualityComparer::Default and perform a spot optimization, because doing the
virtual call would kill performance. C++ templates easily implement the
different comparison cases at compile-time with no runtime overhead, using
type traits and partial specialization.
Or try making a cache that uses a different data structure for small objects
vs big ones, without the consumer having to select the right one.
Multiple inheritance isn't all that useful -- unless you combine it with
CRTP for composition of multiple behaviors. Let's say I had a word
processing control, and a derived class that implements stylus entry
(handwriting recognition). And another derived class that provides skinning
(i.e. select a color scheme). And another one that automatically backed up
the users' data periodically in case of power loss while the app is open.
And another that implements text-to-speech. In C#, is there any way to get
more than one of these behaviors at the same time without reimplementing the
functionality? Not without modifying one of the components to inherit from
a different one. In C++, if you implement CRTP composition or even template
parameter inheritance support then you can build any combination without any
of the variants having prior knowledge of any of the others.
date: Fri, 18 Jul 2008 18:04:06 -0500
author: Ben Voigt [C++ MVP] am
Re: how does C# compare to C++ and VB
On Fri, 18 Jul 2008 16:04:06 -0700, Ben Voigt [C++ MVP]
<rbv@nospam.nospam> wrote:
> Ahh, but lambda's can be traversed as a parse tree instead of turned
> into a
> delegate. The workaround of putting the code in a separate method
> doesn't
> support that.
The use of lambda's as expressions is why I wrote "partially duplicated".
That said, you could in fact construct the parse tree explicitly. The
lambda expression is not _mandatory_. In that sense, "it's just syntax".
> [...]
>> Forgive me if I fail to see the point of the analogy. The "superset"
>> and "subset" relationship mathematics between the kinds of numbers you
>> describe is well-defined. Not so with computer languages, nor the
>> idea of "similar".
>
> So you snipped the (self-evident) example using computer languages. In
> any
> case, "superset" does not imply "similar".
I never said it does. As far as your example being "self-evident", that's
in the eye of the beholder. Suffice to say, I disagree with your claim of
"self-evident", and that is in fact the crux of the point here.
> [...]
> Just you try to make a Dictionary in .NET that supports *any* Key class
> or
> struct without a virtual call to test equality. I suspect that the .NET
> JIT
> is coded to specifically recognize Dictionary or at least
> EqualityComparer::Default and perform a spot optimization, because doing
> the
> virtual call would kill performance. C++ templates easily implement the
> different comparison cases at compile-time with no runtime overhead,
> using
> type traits and partial specialization.
You seem to be making the assumption that this difference represents "more
power". I simply disagree. And again, this is because you are trying to
argue a point ("a language is more powerful than another") before we have
decided to agree on the definition of "more powerful". You have a priori
defined "more powerful" in a way that supports your claim, so of course
your claims seem self-evident to you. But they fail to convince someone
who doesn't agree on the definition.
The other issue is that I've never said that C++ doesn't have features
that C# has. That's not the point. I readily admit the languages are
different. The question is whether C++ has ALL the features C# has. As
far as I know, it doesn't. Certainly the C++ I'm familiar with doesn't.
All that said, your religious view of C++ as _the_ superior language is
intractable, and it's this sort of religious view that I find pointless to
try to debate. Tautological arguments are the norm, openness to
compromise is absent, and I detest such discussions. So I won't bother
you further on the point.
Pete
date: Fri, 18 Jul 2008 17:16:32 -0700
author: Peter Duniho
Re: how does C# compare to C++ and VB
On Fri, 18 Jul 2008 17:30:23 -0700, Arne Vajhøj wrote:
> Peter Duniho wrote:
>> On Fri, 18 Jul 2008 17:15:15 -0700, Arne Vajhøj wrote:
>>> C#<->VB.NET converters are much better than C#<->C++ converters.
>> "much better" == subjective, unquantified opinion.
>
> Should be obvious to anyone with experience in the languages.
Ah, yes...like Ben's "self-evident" comment. Suffice to say, I don't find
that sort of expression a valid debating style. "Should be obvious",
"self-evident", etc. are just crutches for people who don't feel like
proving their point.
> But let us find the last complete program you posted in this
> group > 100 lines. I will find a converter that convert it to
> VB.NET - you will find a converter that converts it to C++
> (not C++/CLI), we post the two here and then people can compare.
>
> OK ?
What would make you think that a single data point in any way represents a
valid study?
> Who on earth would convert manually between C# and VB.NET at all ?
I find myself doing it somewhat regularly, when dealing with different
code examples different people post. The context isn't about getting a
program to work; it's about understanding what someone else has written.
In spite of the fact that the most common scenario is seeing VB.NET code,
I still find it easier to deal with C++ code.
I'm not sure what it is about "my own personal experience" that you are
having trouble comprehending, but that's the bottom line here. None of
your comments regarding machine translation are relevant at all with
respect to my observations about the different languages.
Pete
date: Fri, 18 Jul 2008 17:35:08 -0700
author: Peter Duniho
Re: how does C# compare to C++ and VB
Peter Duniho wrote:
> On Fri, 18 Jul 2008 17:30:23 -0700, Arne Vajhøj wrote:
>> Peter Duniho wrote:
>>> On Fri, 18 Jul 2008 17:15:15 -0700, Arne Vajhøj wrote:
>>>> C#<->VB.NET converters are much better than C#<->C++ converters.
>>> "much better" == subjective, unquantified opinion.
>>
>> Should be obvious to anyone with experience in the languages.
>
> Ah, yes...like Ben's "self-evident" comment. Suffice to say, I don't
> find that sort of expression a valid debating style. "Should be
> obvious", "self-evident", etc. are just crutches for people who don't
> feel like proving their point.
Well - I actually offered a demonstration below. Which makes your
comment above look rather stupid.
>> But let us find the last complete program you posted in this
>> group > 100 lines. I will find a converter that convert it to
>> VB.NET - you will find a converter that converts it to C++
>> (not C++/CLI), we post the two here and then people can compare.
>>
>> OK ?
>
> What would make you think that a single data point in any way represents
> a valid study?
Last 10 so ?
>> Who on earth would convert manually between C# and VB.NET at all ?
>
> I find myself doing it somewhat regularly, when dealing with different
> code examples different people post. The context isn't about getting a
> program to work; it's about understanding what someone else has written.
It is quite common to want to do something manually to learn from it,
but it is rather irrelevant in a discussion of whether it is easy to
do automatically.
Arne
date: Fri, 18 Jul 2008 20:47:06 -0400
author: Arne Vajhøj
Re: how does C# compare to C++ and VB
On Jul 19, 3:04 am, "Ben Voigt [C MVP]" <r...@nospam.nospam> wrote:
> But a simple one you should be very familiar with is
> EqualityComparer::Default
>
> Just you try to make a Dictionary in .NET that supports *any* Key class or
> struct without a virtual call to test equality.
If you mean doing so while keeping the existing interface of
Dictionary, then it's possible, though tricky - once you get the
comparer, you create dynamic methods for all the search operations
that directly invoke the most derived implementation of
IComparer<T>.Compare on the actual comparer instance. In effect, you
still have dynamic dispatch, but it's moved outside the loop where it
kills performance.
In fact, I wouldn't be surprised if JIT was able to lift virtual
method resolution outside the loop on its own, without any dirty Emit
tricks.
On the other hand, if you mean writing my own class with interface
different from that of Dictionary, that's quite doable, too, and will
actually look very similar to std::map:
class Map<TKey, TValue, TComparer>
where TComparer : IComparer, new()
{
readonly TComparer comparer = new TComparer(); // calls to Compare()
on this won't be virtual, and will likely be inlined
}
This is particularly efficient if you then pass an empty struct,
rather than class, as TComparer.
date: Sat, 19 Jul 2008 04:26:56 -0700 (PDT)
author: Pavel Minaev
Re: how does C# compare to C++ and VB
>>> Forgive me if I fail to see the point of the analogy. The
>>> "superset" and "subset" relationship mathematics between the kinds
>>> of numbers you describe is well-defined. Not so with computer
>>> languages, nor the idea of "similar".
>>
>> So you snipped the (self-evident) example using computer languages. In
>> any
>> case, "superset" does not imply "similar".
>
> I never said it does. As far as your example being "self-evident",
> that's in the eye of the beholder. Suffice to say, I disagree with
> your claim of "self-evident", and that is in fact the crux of the
> point here.
Before we forget, here was the example:
"C++ is an almost 100% superset of C89, yet C89 and C99 are far closer to
each other in every respect than to C++."
Do you want to contest that?
>
>> [...]
>> Just you try to make a Dictionary in .NET that supports *any* Key
>> class or
>> struct without a virtual call to test equality. I suspect that the
>> .NET JIT
>> is coded to specifically recognize Dictionary or at least
>> EqualityComparer::Default and perform a spot optimization, because
>> doing the
>> virtual call would kill performance. C++ templates easily
>> implement the different comparison cases at compile-time with no
>> runtime overhead, using
>> type traits and partial specialization.
>
> You seem to be making the assumption that this difference represents
> "more power". I simply disagree. And again, this is because you are
> trying to argue a point ("a language is more powerful than another")
> before we have decided to agree on the definition of "more powerful".
> You have a priori defined "more powerful" in a way that supports your
> claim, so of course your claims seem self-evident to you. But they
> fail to convince someone who doesn't agree on the definition.
>
> The other issue is that I've never said that C++ doesn't have features
> that C# has. That's not the point. I readily admit the languages are
> different. The question is whether C++ has ALL the features C# has. As
> far as I know, it doesn't. Certainly the C++ I'm familiar with
> doesn't.
> All that said, your religious view of C++ as _the_ superior language
> is intractable, and it's this sort of religious view that I find
> pointless to try to debate. Tautological arguments are the norm,
> openness to compromise is absent, and I detest such discussions. So
> I won't bother you further on the point.
I didn't say "superior". Simplicity and barriers to making mistakes are
advantageous in their own right. I said "almost superset" and "more
powerful" and I stand behind that claim.
>
> Pete
date: Mon, 21 Jul 2008 12:49:52 -0500
author: Ben Voigt [C++ MVP] am
Re: how does C# compare to C++ and VB
On Mon, 21 Jul 2008 10:49:52 -0700, Ben Voigt [C++ MVP]
<rbv@nospam.nospam> wrote:
> Before we forget, here was the example:
>
> "C++ is an almost 100% superset of C89, yet C89 and C99 are far closer to
> each other in every respect than to C++."
>
> Do you want to contest that?
I'm not sure what you mean. I do contest that it's an example relevant to
what C# is similar to.
But if all you meant by "self-evident" that the example is, as a
self-contained statement having no implication anywhere else in this
thread, "self-evident", no...I wouldn't have any reason to contest that.
> [...]
> I didn't say "superior". Simplicity and barriers to making mistakes are
> advantageous in their own right. I said "almost superset" and "more
> powerful" and I stand behind that claim.
Well, I find "superior" and "more powerful" practically synonymous. But
more problematic is that you haven't defined "powerful" in a way that
allows for any factual statement to be used using the term. And in
particular, you seem to be using the term differently than I would.
As a tautological assertion, perhaps your claim has basis. But then, any
tautological assertion would. :)
Pete
date: Mon, 21 Jul 2008 11:26:16 -0700
author: Peter Duniho
Re: how does C# compare to C++ and VB
Pavel Minaev wrote:
> On Jul 19, 3:04 am, "Ben Voigt [C++ MVP]" <r...@nospam.nospam> wrote:
>> But a simple one you should be very familiar with is
>> EqualityComparer::Default
>>
>> Just you try to make a Dictionary in .NET that supports *any* Key
>> class or struct without a virtual call to test equality.
>
> If you mean doing so while keeping the existing interface of
> Dictionary, then it's possible, though tricky - once you get the
> comparer, you create dynamic methods for all the search operations
> that directly invoke the most derived implementation of
> IComparer<T>.Compare on the actual comparer instance. In effect, you
> still have dynamic dispatch, but it's moved outside the loop where it
> kills performance.
Congratulations, you can do it by *re-implementing the C++ rules for
templates*. Pretty cool that .NET gives you the dynamic codegen to let you
do it, but still waaaay more difficult than using C++ to do it.
>
> In fact, I wouldn't be surprised if JIT was able to lift virtual
> method resolution outside the loop on its own, without any dirty Emit
> tricks.
>
> On the other hand, if you mean writing my own class with interface
> different from that of Dictionary, that's quite doable, too, and will
> actually look very similar to std::map:
>
> class Map<TKey, TValue, TComparer>
> where TComparer : IComparer, new()
> {
> readonly TComparer comparer = new TComparer(); // calls to Compare()
> on this won't be virtual, and will likely be inlined
> }
>
> This is particularly efficient if you then pass an empty struct,
> rather than class, as TComparer.
They will be virtual unless TComparer is a struct. Which, unfortunately,
EqualityComparer<T> isn't, and EqualityComparer<T>.Default isn't.
But honestly, you've done a great job of working within the confines of .NET
and making the JIT work for you.
date: Mon, 21 Jul 2008 13:38:20 -0500
author: Ben Voigt [C++ MVP] am
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