获取结构体某成员的偏移

#include <iostream>
using namespace std;

#define OFFSSEST(Type,member) size_t(&(((Type*)0)->member))

struct Student
{
    int num;
    char sex;
    int age;
    float score;
};

int main()
{
    Student sdt1;
    Student *ptr=&sdt1;
    cout<<(int)&(ptr->age)<<endl;
    cout<<(int)&(ptr->age)-(int)ptr<<endl;

    size_t offest=OFFSSEST(Student,age);
    cout<<offest<<endl;
    return 0;
}