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Well... you know now how much of a lie it is!
Arguably, theoretically, C++ should be faster because it has a better ahead of time compiler.
But it's also relying on harder to optimize and write library and less elegant compiler constructs... which make it slower...
However C# will slow down at 2 crucial point:
- Start-up. C# start-up time is definitely, humanely perceptibly, slower (because of all the assemblies verification)
- Allegedly real time code can only be reliably be written in C++ as it is, likely easier to write allocation free code, whereas realtime C# slow down on hidden object allocation (although its allocation algorithm are much faster than C++ ones)
- Finally, for laugh, it's just an empty arguments that C++ developer have against C# developer. Surprisingly most of the random comparison code written by random developer make C# wins. But the occasional C++ zealots sometimes come back after a couple of day of profiling and disassembly with a marginally faster C++ version saying that the C++ version was... unoptimized! So... here you have it!
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That's the way I see it. C++ as a religious belief
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I'm not an expert in this but I can tell you this much:
- You didn't set a processor affinity. Stack swaps could have skewed your results.
- You didn't set the process and thread priority to high. Your programs code have been interrupted by other threads.
- Did you make sure you ran both programs with compiler optimization and without debugger/profiler attached?
- Integer-arithmetic isn't representative for the overall speed of the language.
Take a look here: Head-to-head benchmark: C++ vs .NET[^]
If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson
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That article provides a rather thorough comparison, but it focuses on library implementations, not the core language. Just from skimming over the results I spotted several remarks on 'lousy' implementations, and that alone is a dead giveaway that the results should be taken with a huge pint of salt.
GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)
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Thanks for the very informative link!
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3rd point down is crucial. Newbies often forget to ramp up compiler optimisation to -O2 or -O3. Leaving it as the default optimisation level usually sucks.
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You successfully proofed the poor performance of C++ streams.
Just try the C++ version with printf instead of streams and it should be faster.
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Yee I tried printf("%i\n",i);
it is 7 second. That's faster than coutt
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Others have already nailed it down to C++ streams. Besides that I remember reading somewhere that the execution on modern highly parallelized systems also highly depends on the structure of the code.
For example: modern systems would read several machine instructions ahead and analyze them while executing the current one. So if your code would have multiple jump instructions which would prevent effective pipelining this would probably run slower.
Note that I'm not 100% practically sure of what I just wrote. It's theoretical. 
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Tomaž Štih wrote: I'm not 100% practically sure of what I just wrote.
I'd suggest that as a signature for some of our regular Lounge participants. I won't name names. 
There are only 10 types of people in the world, those who understand binary and those who don't.
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I already have it for long time  
M.D.V. 
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
Rating helpful answers is nice, but saying thanks can be even nicer.
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We all know that VB is faster than them both.
cheers
Chris Maunder
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Shirley you mean VB on Rails!
veni bibi saltavi
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Chris Maunder wrote: We all know that VB is faster than them both.
But not as fast as Coopers.
Michael Martin
Australia
"I controlled my laughter and simple said "No,I am very busy,so I can't write any code for you". The moment they heard this all the smiling face turned into a sad looking face and one of them farted. So I had to leave the place as soon as possible."
- Mr.Prakash One Fine Saturday. 24/04/2004
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I had one of these[^] the other day (I was driving - needed something less than full strength) and all I can say is: What were they thinking? 
cheers
Chris Maunder
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Chris Maunder wrote: We all know that VB is faster than them both.
... I assume this is after you accelerated it out the muzzle of a cannon.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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Let's hear it for VB. Hip hip
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So much is impossible to tell. But, as others have mentioned, avoid <iostream> for performance.
There are some very clever template libraries that do printf like behaviour while retaining type-safety. Which are the best of both worlds.
Apart from that, are you timing a release build? C++ typically optimises way more aggressively in release builds.
"If you don't fail at least 90 percent of the time, you're not aiming high enough."
Alan Kay.
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Not anyone I know says C++ *is* faster than C#. Most of the people I hear talking about it say C++ *can be* faster than C#. It's much easier to play memory arithmetic tricks in C++ than C#. You can do it in C# using Memory Pins and Unsafe blocks, but it's a lot more code to write just to get to a point where you can start doing the actual work of manipulating your values.
Also, trivial examples like that won't show you the biggest culprit of performance issues in any .net language: the GC. Once the GC starts grinding away, you can kiss anything that resembles good performance goodbye. You can of course mitigate this by using proper patterns and such, but that's a whole lot of mental overhead that the C++ programmer doesn't need to deal with.
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C++ is filth. For real speed you need C. 
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That depends a lot on whether you want to reuse components such as sort algorithms.
I doubt very much you can match std::sort performance with C code, except for hand-coding every damn sort. Even then, C++ optimisation is damn fine nowadays.
"If you don't fail at least 90 percent of the time, you're not aiming high enough."
Alan Kay.
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Rob Grainger wrote: hand-coding every damn sort
As appropriate for the specific task, yes.
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C is filth. For real speed you need Assembler.
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This link is a blog series done by Raymond Chen and Rico Mariani where Raymond wrote a Chinese dictionary in C++ and Rico wrote a naïve line-by-line translation of the C++ code in C#. The C# code blew away the C++ code in performance.
Raymond then did a number of ever more severe optimizations (including writing his own string class) to finally beat the naïve C# performance. Rico then optimized the C# code and again beat the C++ performance.
Raymond then did a couple of more optimizations to finally beat the C#.
The summary is thus: Doing a straightforward implementation in C# will yield really good performance (and is much quicker to implement, relative to C++), in many cases better than a straightforward implementation in C++. But, if you put in a significant amount of optimization effort, C++ CAN clearly outperform the C# code - as noted in the final blog post of that series, there's certain initial overhead (60ms in Rico's case) that the CLR imposes that you cannot optimize away in C#.
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Gjeltema wrote: is much quicker to implement
Yes, and probably with lower maintenance requirements. As well as C# probably requiring a development team with an overall lower payroll. These are factors that really matter in real-world development. And if the result is "good enough", then call it done and move on.
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