c、c++ 结构体的嵌套

/************************************************************************//* 嵌套结构体                                                                     * C++ **//************************************************************************/struct A {private:	int a1[20];public:	void initialize();	struct B 	{	private:		A *b;		int *p;	public:		void initialize(A *a);		void next();		int read;		void set(int i);	};	friend A::B;};void A::initialize(){	memset(a1, 0, sizeof(a1));}void A::B::initialize(A *a){	b = a;	p = a->a1;}void A::B::set(int i){	*p = i;}/*void main(){	A a;	A::B b1,b2;	int i;	a.initialize();	b1.initialize(&a);	b2.initialize(&a);	for (i =0; i<20; i++)	{		b1.set(i);		b2.set(i);	}}/************************************************************************//* C * 嵌套结构体 *  * *//************************************************************************/ typedef struct A{	int year;	int month;	int day;};typedef struct B {	string name;	int age;	union{		A aa;	}xy;	struct A aa1;};void main(){	B *b1 =NULL;	b1->xy.aa.day =1991;	b1->aa1.month = 7;		getchar();}