计算结构体中成员变量的偏移

#include <iostream>
using namespace std;
#include <stdio.h>
#define offsetof(structure, member) ((int)(&((structure *)0)->member))

struct test_struct
{
	int a;
	char b;
	int aa[10];
	char bb[2];
};

int main()
{
	cout<<offsetof(struct test_struct, a)<<endl;
	cout<<offsetof(struct test_struct, b)<<endl;
	cout<<offsetof(struct test_struct, aa)<<endl;
	cout<<offsetof(struct test_struct, bb)<<endl;
	return 0;
}