为什么 c++ 中 char 和 bool 的大小相同?
我正在阅读 C++ 编程语言. Stroustrup 在其中指出 sizeof(char) == 1 和 1 <= sizeof(bool).具体取决于实施.为什么像布尔值这样简单的值会占用与字符相同的空间?
I'm reading The C++ Programming Language. In it Stroustrup states that sizeof(char) == 1 and 1 <= sizeof(bool). The specifics depend on the implementation. Why would such a simple value as a boolean take the same space as a char?
推荐答案
在现代计算机体系结构中，字节是最小的可寻址内存单元.要将多个位打包到一个字节中，需要应用额外的位移操作.在编译器级别，这是内存与速度要求之间的权衡(在高性能软件中，那些额外的位移操作会不必要地增加和减慢应用程序的速度).
In modern computer architectures, a byte is the smallest addressable unit of memory. To pack multiple bits into a byte requires applying extra bit-shift operations. At the compiler level, it's a trade off of memory vs. speed requirements (and in high-performance software, those extra bit-shift operations can add up and slow down the application needlessly).
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