c - 当我们任意使用 == 时会发生什么？

Question

我尝试在 C 中运行以下代码:

#include <stdio.h>

int main() {
   int a = 10, b = 5, c = 5;
   int d;
   d = b + c == a;
   printf("%d", d);
}

我得到的输出为d = 1。有人可以向我解释一下当我们像这样使用 == 时会发生什么吗？

Answer 1

§6.5.9 (== and !=)-http://c0x.coding-guidelines.com/6.5.9.html

The == (equal to) and != (not equal to) operators are analogous to the relational operators except for their lower precedence.)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.

因此，这里 b+c 等于 a，因为两者的值都是 10，因此它会产生 1 .