定义一个指针变量的内存模型图,以及结构体的偏移量.

BF37F624-581C-4F1A-B409-A25A5F0F012B.png

#include 

typedef struct Teacher{
    char name[64];
    int age;
    char *newname;
}Teacher;

int main(int argc, const char * argv[]) {
    // insert code here...
    printf("Hello, World!\n");
    
    
    int offsize = (int )&(((Teacher *)0)->age);
    printf("%d\n",offsize);//结果是 64
    return 0;
}