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