C ++中char整数值的范围 [英] range for integer values of chars in c++

问题描述

我正在阅读 C ++编程语言，其中Stroustrup指出char的int值范围可以从0到255或-127到127，具体取决于实现方式。这样对吗？似乎应该在-128到127之间。如果没有，为什么在第二个实现可能性中它们只有255个可能的值，而不是256个。

I'm reading The C++ Programming Language and in it Stroustrup states that the int value of a char can range from 0 to 255 or -127 to 127, depending on implementation. Is this correct? It seems like it should be from -128 to 127. If not, why are their only 255 possible values in the second implementation possibility, not 256.

推荐答案

您陷入了二进制补码的思考-C ++标准

You're stuck in two's complement thinking - The C++ standard does not define the representation used for negative numbers!

如果您的计算机（禁止使用上帝）使用一个人的补语代表负数，您在8位字节中的范围是-127到+ 127。从好的方面来说，您有两种可能的零表示形式。

If your computer (god forbid) uses ones's complement to represent negative numbers, you have a range of -127 to + 127 in an 8-bit byte. On the upside, you have two different possible representations for zero...

但是，在现实世界中，您不太可能会遇到一个人的补码计算机。

However, in the real world, you're unlikely to meet a one's complement computer.

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