这ç数据类型可以重新present一个40位二进制数？ [英] Which C datatype can represent a 40-bit binary number?

问题描述

我需要重新present一个40位二进制数。这ç数据类型应该用于处理？

I need to represent a 40-bit binary number. Which C datatype should be used to handle this?

推荐答案

如果您使用的是C99或C11兼容的编译器，然后用 int_least64_t 的最大兼容性。或者，如果你想要一个无符号的类型， uint_least64_t 。这些都是在这两个定义的＆LT; stdint.h＆GT;

If you're using a C99 or C11 compliant compiler, then use int_least64_t for maximum compatibility. Or, if you want an unsigned type, uint_least64_t. These are both defined in <stdint.h>

＆LT; stdint.h＆GT; 通常还定义的int64_t ，但因为它不是由标准的要求，但可能不会在每一个实施进行定义。但是：

<stdint.h> usually also defines int64_t, but since it's not required by the standard, it may not be defined in every implementation. However:

• int_least64_t - 至少有64位，和


• int_fast64_t - 在此实现至少有64位最快尺寸

• int_least64_t - at least 64 bits, and
• int_fast64_t - the fastest size in this implementation of at least 64 bits

都要求在C99和C11 present（见C99标准§7.18.1.2-3，并在C11标准§7.20.1.2-3）。

are both required to be present in C99 and C11 (See § 7.18.1.2-3 in the C99 standard, and § 7.20.1.2-3 in the C11 standard).

虽然C99指定长长 至少在一个特定的机（第5.2.4.2.1）64位，在 ＆LT; stdint.h方式＆gt; 被设计成便携式明确

Although C99 specifies that long long is at least 64 bits on a particular machine (§ 5.2.4.2.1), the types in <stdint.h> are designed to be explicitly portable.

您可以阅读更多关于整数大小不同的平台上这里。
需要注意的是整数类型的大小都与长数据类型的问题 - 在64位的Windows，这是目前32位，而在64位Linux是64位。出于这个原因，我相信你是最安全的使用类型从＆LT; stdint.h＆GT;

You can read more about integer sizes on different platforms here. Note that the size of integer types are a problem with the long data type - on 64 bit Windows, it's currently 32 bits, whereas on 64 bit linux it's 64 bits. For this reason, I believe you're safest using the types from <stdint.h>

这是值得注意的是，有些人觉得长长更具有可读性。就个人而言，我preFER从＆LT的类型; stdint.h＆GT; ，因为他们让你说你是什么意思时，你使用它们 - 我觉得这更易读。当然，可读性往往是口味的问题 - 如果你使用现有的codeBase的工作，我只是跟着无论他们做什么：）

It's worth noting that some feel that long long is more readable. Personally, I prefer the types from <stdint.h>, because they allow you to say what you mean when you use them - which I find more readable. Of course, readability is often a matter of taste - and if you're working with an existing codebase, I'd just follow whatever they do :)

如果你的编译器只支持C89，那么<一个href=\"http://stackoverflow.com/questions/9595225/which-c-datatype-can-re$p$psent-a-40-bit-binary-number/9596246#9596246\">R..'s解决方案将让你到整数precision的53位。

If your compiler only supports C89, then R..'s solution will allow you up to 53 bits of integer precision.

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