C标准是否将真值显式表示为0或1？(Does the C standard explicitly indicate truth value as 0 or 1?)

C标准是否将真值显式表示为0或1？(Does the C standard explicitly indicate truth value as 0 or 1?)

我们知道任何不等于0数字都被认为是C，所以我们可以写：

int a = 16; while (a--) printf("%d\n", a); // prints numbers from 15 to 0

但是，我想知道在C中是否将/ F值定义为1/0，所以我尝试了以下代码：

printf("True = %d, False = %d\n", (0 == 0), (0 != 0)); // prints: True = 1, False = 0

C标准是否明确地将true和false的真值分别表示为1和0 ？

We know that any numbers that are not equal to 0 are viewed as true in C, so we can write:

int a = 16; while (a--) printf("%d\n", a); // prints numbers from 15 to 0

However, I was wondering whether true / false are defined as 1/0 in C, so I tried the code below:

printf("True = %d, False = %d\n", (0 == 0), (0 != 0)); // prints: True = 1, False = 0

Does C standard explicitly indicate the truth values of true and false as 1 and 0 respectively?

最满意答案

C标准是否明确地将真值和true值分别表示为0和1 ？

C标准将stdbool.h中的宏定义为true和false ，分别扩展为1和0 。

C11-§7.18：

其余三个宏适用于#if预处理指令。 他们是

true

其扩展到整数常数1 ，

false

它扩展到整数常数0 [...]

关于运算符==和!=

C11-§6.5.9/ 3：

== （等于）和!= （不等于）运算符类似于关系运算符，除了它们的较低优先级。 ^108）如果指定的关系为真，则每个运算符产生1如果为false则返回0 。 结果具有int类型。 对于任何一对操作数，其中一个关系是正确的。

Does the C standard explicitly indicate the truth values of true and false as 0 and 1 respectively?

The C standard defines true and false as macros in stdbool.h which expand to 1 and 0 respectively.

C11-§7.18:

The remaining three macros are suitable for use in #if preprocessing directives. They are

true

which expands to the integer constant 1,

false

which expands to the integer constant 0 [...]

Regarding the operators == and !=

C11-§6.5.9/3:

The == (equal to) and != (not equal to) operators are analogous to the relational operators except for their lower precedence.¹⁰⁸⁾ Each of the operators yields 1 if the specified relation is true and 0 if it is false. The result has type int. For any pair of operands, exactly one of the relations is true.