毕竟，答案总要在某个地方，不是吗?：）

嗯,没有。

正如一些回复所指出的那样，这个问题在某种程度上没有得到充分的说明，只会引起问题的回应，而不是答案。只从一个方面来说:

这个问题将语言和语言实现合并在一起——这个C程序比c#程序慢2194倍，快1.17倍——我们不得不问你:哪种语言实现?

然后是哪些项目?哪个机器?哪些操作系统?哪个数据集?

我知道这不是你想问的，但是c#通常比c++写得更快，这在商业环境中是一个很大的好处。

In theory, for long running server-type application, a JIT-compiled language can become much faster than a natively compiled counterpart. Since the JIT compiled language is generally first compiled to a fairly low-level intermediate language, you can do a lot of the high-level optimizations right at compile time anyway. The big advantage comes in that the JIT can continue to recompile sections of code on the fly as it gets more and more data on how the application is being used. It can arrange the most common code-paths to allow branch prediction to succeed as often as possible. It can re-arrange separate code blocks that are often called together to keep them both in the cache. It can spend more effort optimizing inner loops.

我怀疑。net或任何jre都能做到这一点，但早在我上大学的时候就有人在研究这一点，所以认为这类东西很快就会在现实世界中找到自己的方式也不是不合理的。

快了5个橘子。或者更确切地说:不可能有一个(正确的)笼统的答案。c++是一种静态编译语言(但也有配置文件引导的优化)，c#在JIT编译器的帮助下运行。它们之间的差异如此之大，以至于像“快了多少”这样的问题都无法回答，甚至无法给出数量级。

在一个特殊的场景中，c++仍然占据上风(并且将在未来几年占据上风)，即可以在编译时预先确定多态决策。

通常，封装和延迟决策是一件好事，因为它使代码更加动态，更容易适应不断变化的需求，并且更容易作为框架使用。这就是为什么在c#中面向对象编程是非常高效的，并且它可以在术语“泛化”下泛化。不幸的是，这种特殊的泛化在运行时是有代价的。

Usually, this cost is non-substantial but there are applications where the overhead of virtual method calls and object creation can make a difference (especially since virtual methods prevent other optimizations such as method call inlining). This is where C++ has a huge advantage because you can use templates to achieve a different kind of generalization which has no impact on runtime but isn't necessarily any less polymorphic than OOP. In fact, all of the mechanisms that constitute OOP can be modelled using only template techniques and compile-time resolution.

在这种情况下(不可否认，它们通常局限于特殊的问题领域)，c++胜过c#和类似的语言。

We have had to determine if C# was comparable to C++ in performance and I wrote some test programs for that (using Visual Studio 2005 for both languages). It turned out that without garbage collection and only considering the language (not the framework) C# has basically the same performance as C++. Memory allocation is way faster in C# than in C++ and C# has a slight edge in determinism when data sizes are increased beyond cache line boundaries. However, all of this had eventually to be paid for and there is a huge cost in the form of non-deterministic performance hits for C# due to garbage collection.