[C++知识库]C语言中的匿名结构体

在 C 的 C11 标准中，添加了匿名结构和匿名联合。
匿名联合/结构也称为未命名联合/结构，由于没有名称，因此不会创建它们的直接对象（或变量），通常我们在嵌套结构或联合中使用它们。

An anonymous struct declaration is a declaration that declares neither a tag for the struct, nor an object or typedef name. Anonymous structs are not allowed in C++.

举例：

// C Program to demonstrate working of anonymous struct
#include <stdio.h>  
struct scope
{
	// Anonymous structure
	struct 
	{
		char alpha;
		int num;
	};
};

int main(void)
{
	struct scope x;
	x.num = 65;
	x.alpha = 'B';

	// Note that members of structure are accessed directly
	printf("x.alpha = %c, x.num = %d\n", x.alpha, x.num);

	return 0;
}

参考资料：
【1】https://www.geeksforgeeks.org/g-fact-38-anonymous-union-and-structure/
【2】https://docs.oracle.com/cd/E19205-01/819-5267/bkael/index.html