c语言并没有什么特别之处，这也是它速度快的原因之一。

新语言支持垃圾收集、动态类型和其他功能，使程序员更容易编写程序。

问题在于，会有额外的处理开销，这会降低应用程序的性能。C语言没有这些，这意味着没有开销，但这意味着程序员需要能够分配内存并释放它们以防止内存泄漏，并且必须处理变量的静态类型。

也就是说，许多语言和平台，如Java(其Java虚拟机)和。net(其公共语言运行时)，多年来通过即时编译(从字节码生成本机机器代码以实现更高性能)等技术改进了性能。

主要的因素是它是一种静态类型的语言，可以编译为机器代码。此外，由于它是一种低级语言，它通常不会做任何您不让它做的事情。

这些是我想到的其他一些因素。

Variables are not automatically initialized No bounds checking on arrays Unchecked pointer manipulation No integer overflow checking Statically-typed variables Function calls are static (unless you use function pointers) Compiler writers have had lots of time to improve the optimizing code. Also, people program in C for the purpose of getting the best performance, so there's pressure to optimize the code. Parts of the language specification are implementation-defined, so compilers are free to do things in the most optimal way

大多数静态类型语言的编译速度可以和C语言一样快，甚至比C语言更快，特别是如果它们可以假设C语言因为指针别名等原因而不能这样做的话。

一些c++算法比C快，其他语言中的算法或设计模式的一些实现可能比C快。

当人们说C语言很快，然后转向谈论其他语言时，他们通常是在用C语言的性能作为基准。

C的设计者们已经做出了取舍。也就是说，他们决定把速度放在安全之上。C不会

检查数组下标边界 检查未初始化的变量值 检查内存泄漏 检查空指针解引用

当你索引到一个数组时，在Java中，它接受虚拟机中的一些方法调用，绑定检查和其他健全检查。这是有效的，绝对没问题，因为它在应有的地方增加了安全性。但是在C语言中，即使是非常微不足道的东西也不会被放在安全的地方。例如，C不要求memcpy检查要复制的区域是否重叠。它并不是一种用于编写大型商业应用程序的语言。

但是这些设计决策并不是C语言中的bug。它们是被设计出来的，因为它允许编译器和库编写者从计算机中获得每一点性能。下面是C语言的精神——C语言的基本原理文档是这样解释的:

C code can be non-portable. Although it strove to give programmers the opportunity to write truly portable programs, the Committee did not want to force programmers into writing portably, to preclude the use of C as a ``high-level assembler'': the ability to write machine-specific code is one of the strengths of C. Keep the spirit of C. The Committee kept as a major goal to preserve the traditional spirit of C. There are many facets of the spirit of C, but the essence is a community sentiment of the underlying principles upon which the C language is based. Some of the facets of the spirit of C can be summarized in phrases like Trust the programmer. Don't prevent the programmer from doing what needs to be done. Keep the language small and simple. Provide only one way to do an operation. Make it fast, even if it is not guaranteed to be portable. The last proverb needs a little explanation. The potential for efficient code generation is one of the most important strengths of C. To help ensure that no code explosion occurs for what appears to be a very simple operation, many operations are defined to be how the target machine's hardware does it rather than by a general abstract rule. An example of this willingness to live with what the machine does can be seen in the rules that govern the widening of char objects for use in expressions: whether the values of char objects widen to signed or unsigned quantities typically depends on which byte operation is more efficient on the target machine.

这是自动和手动的区别，高级语言是抽象的，因此是自动化的。C/ c++是人工控制和处理的，甚至错误检查代码有时也是人工劳动。

C和c++也是编译语言，这意味着没有任何一种语言可以在任何地方运行，这些语言必须针对您使用的硬件进行微调，从而增加了额外的隐患。尽管现在C/ c++编译器在所有平台上变得越来越普遍，这有点令人不安。您可以在平台之间进行交叉编译。这仍然不是一个到处运行的情况，你基本上是在指示编译器a针对编译器B编译相同的代码，不同的架构。

归根结底，C语言并不意味着容易理解或推理，这也是为什么它们被称为系统语言。他们出现在所有高层次抽象的废话之前。这也是为什么它们不用于前端web编程。他们只是不适合这项任务，他们的意思是解决传统语言工具无法解决的复杂问题。

这就是为什么你会得到一些疯狂的东西(微架构、驱动程序、量子物理、AAA游戏、操作系统)，这些东西C和c++非常适合。速度和数据处理是主要领域。

The fastest running code would be carefully hand crafted machine code. Assembler will be almost as good. Both are very low level and it takes a lot of writing code to do things. C is a little above assembler. You still have the ability to control things at a very low level in the actual machine, but there is enough abstraction make writing it faster and easier then assembler. Other languages such as C# and JAVA are even more abstract. While Assembler and machine code are called low level languages, C# and JAVA (and many others) are called high level languages. C is sometimes called a middle level language.