条件分配给布尔 [英] Condition assignment to boolean

问题描述

仿效​​布尔值可以做到这样的：

Emulating booleans in C can be done this way:

int success;
success = (errors == 0 && count > 0);
if(success)
   ...

使用 stdbool.h 收入以下可以做的：

With stdbool.h included following could be done:

bool success;
success = (errors == 0 && count > 0) ? true : false;
if(success)
   ...

据我了解的逻辑和比较操作应该返回1或0。
此外， stdbool.h 常量应该这样定义：真正的== 1 和 =假= 0 。

From what I understand logical and comparison operators should return either 1 or 0. Also, stdbool.h constants should be defined so that true == 1 and false == 0.

因此​​，下面应该工作：

Thus following should work:

bool success;
success = (errors == 0 && count > 0);
if(success)
   ...

和它上了我与测试它的编译器工作。但它是安全的假设它是便携式code？ （假设 stdbool.h 存在）

And it does work on compilers that I have tested it with. But is it safe to assume it is portable code? (Assume that stdbool.h exists)

是C ++编译器不同的情况为布尔是内部类型？

Is the situation different on C++ compilers as bool is internal type?

推荐答案

这是安全的假设。在C99，在转换到 _Bool 类型，所有非零值转换为1，这在6.3.1.2节在C99标准描述。平等和关系运算符（如 == ，＆GT; = 等），保证导致1或0为好。这是在第6.5.8和6.5.9描述。

It is safe to assume. In C99, upon conversion to the _Bool type, all non-zero values are converted to 1. This is described in section 6.3.1.2 in the C99 standard. The equality and relational operators (e.g. ==, >=, etc) are guaranteed to result in either 1 or 0 as well. This is described in section 6.5.8 and 6.5.9.

有关C ++中，布尔类型是一个真正的布尔类型，其中值转换为真正或假 == 操作等来一个<$> C $ C>布尔，并期望它的工作，因为关系和比较操作导致布尔反正。当真正转换为整数类型它转换为1。

For C++, the bool type is a real Boolean type where values are converted to true or false rather than 1 or 0, but it is still safe to assign the result of an == operation etc. to a bool and expect it to work, because the relational and comparison operators result in a bool anyway. When true is converted to an integer type it is converted to 1.

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