c++ anonymous union,struct -- 匿名联合体和机构体
结构体和联合体各自的基本用法不赘述，仅说一下他们匿名时访问的情况。如果是token不同，可以直接跨层访问。例子
#include <iostream>
using namespace std;
struct zoo_obj{
string name;
union {
unsigned int property;
struct{ //plant
unsigned int
hasLeaf:1,
hasFlower:1,
hasTrunk:1,
hasRattan:1;
};
struct { //animal
unsigned int
isBackbone:1,
isOvipara:1,
hasLags:1,
hasWing:1;
};
};
};
int main(void)
{
zoo_obj peony = {"peony",0};
zoo_obj dog = {name:"dog",0};
dog.hasLags = true;
/* zoo_obj dog = {name:"dog",property:0};
* sorry, unimplemented: non-trivial designated initializers
* not supported
*/
cout << peony.name << " hasLeaf " << peony.hasLeaf << endl;
cout << dog.name << " hasLags " << dog.hasLags << endl;
}
输出
peony hasLeaf 0
dog hasLags 1
不支持像列子中name样的指定访问。如果指定了会报错
sorry, unimplemented: non-trivial designated initializers not supported
