Everyone says c++ is faster than c#, why?
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I used same algorithm for c# and c++. I have read c++ is faster than c# but my tests shows c# is faster than c++. What's wrong? My codes like this. c++ is 36 seconds
#include
#includeusing namespace std;
int main(){
const clock_t beginTime = clock();
for (int i = 2; i < 2000000; i++)
{
bool isPrime = true;
for (int j = 2; j*j <= i; j++)
{
if (i%j == 0){
isPrime = false;
break;
}
}
if (isPrime)
cout << i << endl;
}
cout << float(clock() - beginTime) / CLOCKS_PER_SEC;
}c# is 9 seconds
using System;
namespace Console01
{
class Program
{static void Main(string\[\] args) { DateTime beginTime = DateTime.Now; for (int i = 2; i <= 2000000; i++) { bool isPrime = true; for (int j = 2; j \* j < i; j++) { if (i % j == 0) { isPrime = false; break; } } if (isPrime) Console.WriteLine(i); } TimeSpan ts = DateTime.Now - beginTime; Console.WriteLine(ts.Seconds); } }}
You're timing cout.
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I used same algorithm for c# and c++. I have read c++ is faster than c# but my tests shows c# is faster than c++. What's wrong? My codes like this. c++ is 36 seconds
#include
#includeusing namespace std;
int main(){
const clock_t beginTime = clock();
for (int i = 2; i < 2000000; i++)
{
bool isPrime = true;
for (int j = 2; j*j <= i; j++)
{
if (i%j == 0){
isPrime = false;
break;
}
}
if (isPrime)
cout << i << endl;
}
cout << float(clock() - beginTime) / CLOCKS_PER_SEC;
}c# is 9 seconds
using System;
namespace Console01
{
class Program
{static void Main(string\[\] args) { DateTime beginTime = DateTime.Now; for (int i = 2; i <= 2000000; i++) { bool isPrime = true; for (int j = 2; j \* j < i; j++) { if (i % j == 0) { isPrime = false; break; } } if (isPrime) Console.WriteLine(i); } TimeSpan ts = DateTime.Now - beginTime; Console.WriteLine(ts.Seconds); } }}
"my tests shows c# is faster than c++" No they don't. You showed that ONE C# program ran faster than ONE C++ program. Sheesh.
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After a quick check, what you're really comparing here is the efficiency of
Console.WriteLinevscoutIf you swapcoutforprintfyou get much more similar times. In my case the C++ was a second faster than the C# but it's not a very fair comparison. Really I don't think you'll find much difference in performance of either. -
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!
All in one Menu-Ribbon Bar DirectX for WinRT/C# since 2013! Taking over the world since 1371!
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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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I used same algorithm for c# and c++. I have read c++ is faster than c# but my tests shows c# is faster than c++. What's wrong? My codes like this. c++ is 36 seconds
#include
#includeusing namespace std;
int main(){
const clock_t beginTime = clock();
for (int i = 2; i < 2000000; i++)
{
bool isPrime = true;
for (int j = 2; j*j <= i; j++)
{
if (i%j == 0){
isPrime = false;
break;
}
}
if (isPrime)
cout << i << endl;
}
cout << float(clock() - beginTime) / CLOCKS_PER_SEC;
}c# is 9 seconds
using System;
namespace Console01
{
class Program
{static void Main(string\[\] args) { DateTime beginTime = DateTime.Now; for (int i = 2; i <= 2000000; i++) { bool isPrime = true; for (int j = 2; j \* j < i; j++) { if (i % j == 0) { isPrime = false; break; } } if (isPrime) Console.WriteLine(i); } TimeSpan ts = DateTime.Now - beginTime; Console.WriteLine(ts.Seconds); } }}
Hi, I compiled and ran the program at home using g++. The printing version was 5.6 seconds and a non printing version was 4.62 seconds. much better than both those times. C# also has the overhead on the .NET runtime. And the C++ program just has the c++ standary libray for overhead. c++ is fully compiled and c# is tokenized and still needs to be processed by the JIT.
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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
-
I used same algorithm for c# and c++. I have read c++ is faster than c# but my tests shows c# is faster than c++. What's wrong? My codes like this. c++ is 36 seconds
#include
#includeusing namespace std;
int main(){
const clock_t beginTime = clock();
for (int i = 2; i < 2000000; i++)
{
bool isPrime = true;
for (int j = 2; j*j <= i; j++)
{
if (i%j == 0){
isPrime = false;
break;
}
}
if (isPrime)
cout << i << endl;
}
cout << float(clock() - beginTime) / CLOCKS_PER_SEC;
}c# is 9 seconds
using System;
namespace Console01
{
class Program
{static void Main(string\[\] args) { DateTime beginTime = DateTime.Now; for (int i = 2; i <= 2000000; i++) { bool isPrime = true; for (int j = 2; j \* j < i; j++) { if (i % j == 0) { isPrime = false; break; } } if (isPrime) Console.WriteLine(i); } TimeSpan ts = DateTime.Now - beginTime; Console.WriteLine(ts.Seconds); } }}
std::endl is not equivalent to '\n' but also flushes the buffer. Try to change endl by '\n'
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Ygnaiih wrote:
Told you up front I'm not a liberal
Ya, I was making a silly joke.
Ygnaiih wrote:
if you want to do a political discussion, code project is not the place for it.
Actually, it is, but not in the Lounge. The Soapbox is the place for it. However, John wasn't making any political statements. :doh:
There are only 10 types of people in the world, those who understand binary and those who don't.
I'll Trump yours and give you a bit of Sanders.
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I used same algorithm for c# and c++. I have read c++ is faster than c# but my tests shows c# is faster than c++. What's wrong? My codes like this. c++ is 36 seconds
#include
#includeusing namespace std;
int main(){
const clock_t beginTime = clock();
for (int i = 2; i < 2000000; i++)
{
bool isPrime = true;
for (int j = 2; j*j <= i; j++)
{
if (i%j == 0){
isPrime = false;
break;
}
}
if (isPrime)
cout << i << endl;
}
cout << float(clock() - beginTime) / CLOCKS_PER_SEC;
}c# is 9 seconds
using System;
namespace Console01
{
class Program
{static void Main(string\[\] args) { DateTime beginTime = DateTime.Now; for (int i = 2; i <= 2000000; i++) { bool isPrime = true; for (int j = 2; j \* j < i; j++) { if (i % j == 0) { isPrime = false; break; } } if (isPrime) Console.WriteLine(i); } TimeSpan ts = DateTime.Now - beginTime; Console.WriteLine(ts.Seconds); } }}
Muharrem B. wrote:
Everyone says c++ is faster than c#, why?
Because "everyone" doesn't know what they are talking about when then make a statement like that. First of course in pantheon of programming speed is of small consequence. Microsoft, google and apple are not successful because of speed but rather because they make money. Businesses that don't make money do not last. And developers that think technology is more important than sales end up working for companies that don't make money. Second of course there can be actual business reasons where 'speed' is important but in the vast, vast majority of cases actually producing speed is based on factors besides just code and language. Third when in fact something needs to be faster it is experience not code that actually leads to faster solutions. Someone with years of experience is much more likely to produce a 'fast' system than someone without that experience regardless of technology choice. Keep in mind however that that is an average an not an absolute. Fourth, benchmarks, which is what you have, is pretty much useless in determining speed as far as it means anything in the business world. They often reflect nothing but one small aspect of the language and platform on which they run. That is if they are down well. Poorly done they often reflect a misunderstanding of how languages, platforms and even benchmarks work. Very rarely they even reflect a biased attempt to achieve a specific result. Fifth if one really wants to actually focus on professional programming then one should focus on understanding the basics on what it means to create a system and not language specifics. Basic one would be to understand that performance is impacted in the following way 1. Requirements, most impact 2. Design (including explicit and implicit.) 3. platform 4. language least impact Basic two would be to understand that if one wants to get more performance out of an application (not a system) and one can only focus on 4 in the above then one must do the following 1. Learn how to use an application profiler 2. Learn how to simulate real business data in the application 3. Run the profiler and determine where it might actually be possible to improve performance. Focusing on 1/2 in the above can achieve orders of magnitude impacts on performance while 4 can only achieve marginal percentage increases. After all of that my personal opinion is that if one had an unlimited amoun
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I used same algorithm for c# and c++. I have read c++ is faster than c# but my tests shows c# is faster than c++. What's wrong? My codes like this. c++ is 36 seconds
#include
#includeusing namespace std;
int main(){
const clock_t beginTime = clock();
for (int i = 2; i < 2000000; i++)
{
bool isPrime = true;
for (int j = 2; j*j <= i; j++)
{
if (i%j == 0){
isPrime = false;
break;
}
}
if (isPrime)
cout << i << endl;
}
cout << float(clock() - beginTime) / CLOCKS_PER_SEC;
}c# is 9 seconds
using System;
namespace Console01
{
class Program
{static void Main(string\[\] args) { DateTime beginTime = DateTime.Now; for (int i = 2; i <= 2000000; i++) { bool isPrime = true; for (int j = 2; j \* j < i; j++) { if (i % j == 0) { isPrime = false; break; } } if (isPrime) Console.WriteLine(i); } TimeSpan ts = DateTime.Now - beginTime; Console.WriteLine(ts.Seconds); } }}
Because its not. 1) Did you run with the debugger attached? 2) Did you build in "release" configuration? 3) Are the builds both running in x86 or x64? 4) What C++ and C#/.NET compiler are you using? Almost nothing is faster in C# when doing numerical calculations like this. Usually only stuff where the GC has some kind of benefit in performance be delaying de-allocation.
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I used same algorithm for c# and c++. I have read c++ is faster than c# but my tests shows c# is faster than c++. What's wrong? My codes like this. c++ is 36 seconds
#include
#includeusing namespace std;
int main(){
const clock_t beginTime = clock();
for (int i = 2; i < 2000000; i++)
{
bool isPrime = true;
for (int j = 2; j*j <= i; j++)
{
if (i%j == 0){
isPrime = false;
break;
}
}
if (isPrime)
cout << i << endl;
}
cout << float(clock() - beginTime) / CLOCKS_PER_SEC;
}c# is 9 seconds
using System;
namespace Console01
{
class Program
{static void Main(string\[\] args) { DateTime beginTime = DateTime.Now; for (int i = 2; i <= 2000000; i++) { bool isPrime = true; for (int j = 2; j \* j < i; j++) { if (i % j == 0) { isPrime = false; break; } } if (isPrime) Console.WriteLine(i); } TimeSpan ts = DateTime.Now - beginTime; Console.WriteLine(ts.Seconds); } }}
C# or rather the .Net runtime does a number of things to make code "safer". These are things like bounds checking, type safety, etc. Some of that happens at compile time, but of necessity a lot of it happens at run time. This obviously takes time. Much of it can be "turned off" if you want to though you may not want to. If you want very tight control of timing then C++ and likely straight C is a better bet. For a variety of problems .Net (and therefore C#) is performant enough and "safer" than C or C++. It is good to have options. Pat O