bool在内部如何存储? [英] How is bool internally stored?

问题描述

我假设bool变量默认情况下可以容纳true或false值，但是当我运行此代码段时，我知道默认值是未定义的.
我尝试打印bTest值并在每次运行时获得不同的输出.这是否意味着bool等同于未签名的char?

int main() {
bool bTest;
if(bTest != true && bTest != false)
printf("bool default value is undefined - %d",bTest);
return 0;

)

解决方案

在内部，布尔值以字节存储，并且(与其他任何未初始化的变量一样)它将具有随机"值-实际上这是十六进制CC-与true(1)或false(0)的值不匹配

虽然仅使用一个位来存储布尔变量会节省空间，但使用字节则要更节省处理器:位操作比字节需要更多的组装步骤！全部，
谢谢您的答复，所以仅需总结一下-bool可以在为其分配的内存空间中使用该值，在调试模式下，它会给出警告-该变量未初始化，在发行版中，我们必须确保我们正在使用分配给它的值.

Hi,
I assumed that bool variable can hold either true or false values by default,but when I ran this code snippet I got to know that default value is undefined.
I tried to print the bTest value and got different outputs at each run.Does that mean that bool is equivalent to unsigned char?

int main() {
bool bTest;
if(bTest != true && bTest != false)
printf("bool default value is undefined - %d",bTest);
return 0;

)

解决方案

Internally, a bool is stored as a byte, and (like any other uninitialized variable) it will have a "random" value - in practice this is hex CC - which does not match the value of true (1) or false (0)

While it would be more space efficient to use only a single bit to store a bool, it is far more processor efficient to use a byte: bit operations need more assembly steps than byte!

Hi all,
thanks for your replies,so just to conclude - bool can have the value present in the memory space it is assigned with,in debug mode it gives a warning - that variable is uninitialized ,in release we have to make sure we are using it assigned.

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