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Is C++ still needed?

gerd-riesselmann.net

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Re: Is C++ still needed?

#21

Post by Nelson69 »

tamas wrote: post #19
vilya wrote: post #15

Earlier quoted context omitted.

Reading the article, it sounded like he was comparing the speed of some unspecified ORM library in each language. If so, I suspect he may have been comparing a naive hand-rolled implementation in C++ to something like Hibernate/NHibernate which has many years of development and optimisation behind it. The lessons to draw from this, if any, are that C++ code isn't automatically faster than Java or C# code: you have to…

Actually, object creation on the heap can be quite slower in C++ than in Java, at least if you are not using a custom allocator. The standard allocator in C++(using malloc) is SLOW.

The original article was terrible, so normally I wouldn't comment but I'll attempt to improve the discussion..

Do applications in C++ get modeled the same way as they would in Java or C#? Allocation speed doesn't quite seem like an apples to apples comparison.

Re: Is C++ still needed?

#22

Post by calcnerd256 »

dkersten wrote: post #14
chanux wrote: post #6

"Conclusion? C++ sometimes is the best choice, sometimes not." Isn't that the case for any programing language?

Well... not "any", theres some I can't really see would ever be the "best" choice. Lolcode anyone? (I'm sure theres non-joke languages too)

obligatory mention of brainf

Re: Is C++ still needed?

#23

Post by tamas »

Nelson69 wrote: post #21
tamas wrote: post #19

Earlier quoted context omitted.

Actually, object creation on the heap can be quite slower in C++ than in Java, at least if you are not using a custom allocator. The standard allocator in C++(using malloc) is SLOW.

The original article was terrible, so normally I wouldn't comment but I'll attempt to improve the discussion.. Do applications in C++ get modeled the same way as they would in Java or C#? Allocation speed doesn't quite seem like an apples to apples comparison.

If by being modeled you are asking whether objects are used in C++ as in Java/C#, then I would say yes, maybe even more so. Of course in C++ there is a possibility to use it as a "C with some more stuff" language, and unfortunately it is used as such regularly. But well designed C++ code involves object usage quite similar to Java/C#. Also in C++, RAII is used for managing transient resources, and this probably introduce extra objects which in Java would not be created.

For example: Creating a temporary file and after some work deleting it would be done using try & finally sections in idiomatic Java, but in C++ an object would be used where the constructor contains the file creation and the destructor contains the deletion. This way the file lifetime is tied strictly to the object lifetime, which would be destroyed automatically when the code block is left.

However, the fact that object allocation on the heap is slow is mitigated by having the ability to create objects on the stack, which is probably even faster than Java or C#. And they are also managed automatically, so stack objects are always preferred if they are suitable.

While I think it is an apple-to-apple comparison, it is a microbenchmark, and as such probably irrelevant in most of the real-world cases.

Re: Is C++ still needed?

#24

Post by steiger »

olliesaunders wrote: post #13

It's difficult to imagine games being written in Java or C# and being faster than C++.

Some say that Jake 2 ( http://en.wikipedia.org/wiki/Jake2 ) actually ran faster than Quake 2. Of course there are a number of points to consider here, like the oldness of the Quake 2 code (thus a lack of optimization for modern computers).

Anyway, just a curiosity :)

Re: Is C++ still needed?

#25

Post by humbledrone »

stonemetal wrote: post #10
DanielBMarkham wrote: post #7

With all due respect, this guy doesn't know what he's talking about. There might be a case to be made to eliminate C++, but it's best made by somebody who knows more than this guy. This is really a terrible submission.

In what way? As far as I can tell point 1 is true memory allocation in C# is faster than in C++. Point 2 not so much unless you are starting out fresh and have no libraries beyond the standard library, and really how often is memory allocation really such a bottle neck that you write your own allocator? Point 3 true of pretty much every language that isn't C. Sure there are bridges to specific languages like boost.py…

There's no way that real memory allocation is faster in C# than in C++. I don't know much about the CLR, but if it appears to allocate memory faster, it is probably because it is taking the memory from a pool which it has already allocated from the OS. You can do that in C++ if you want, using e.g. boost::pool.

Re: Is C++ still needed?

#26

Post by humbledrone »

FTA: "C++ isn't open to other languages"

Obviously the author has not heard of boost::python -- it provides an extremely easy way to interface Python and C++, including classes in one language that inherit from classes in the other.

EDIT: Oh, yeah, and SWIG.

Re: Is C++ still needed?

#27

Post by stonemetal »

humbledrone wrote: post #25
stonemetal wrote: post #10

Earlier quoted context omitted.

In what way? As far as I can tell point 1 is true memory allocation in C# is faster than in C++. Point 2 not so much unless you are starting out fresh and have no libraries beyond the standard library, and really how often is memory allocation really such a bottle neck that you write your own allocator? Point 3 true of pretty much every language that isn't C. Sure there are bridges to specific languages like boost.py…

There's no way that real memory allocation is faster in C# than in C++. I don't know much about the CLR, but if it appears to allocate memory faster, it is probably because it is taking the memory from a pool which it has already allocated from the OS. You can do that in C++ if you want, using e.g. boost::pool.

As with most compacting collecting languages memory allocation is a space check and a pointer increment. In C++ new has to do quite a bit more. It is about Java but C# is capable of the same. http://www.ibm.com/developerworks/java/library/j-jtp09275.ht...

Also note that C++'s memory model is "single threaded" new must grab a global lock where as C#'s memory allocator is designed with threads in mind so no locking overhead.

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