引用C结构而不引用成员

Question

typedef struct s {
  int x;
  int y;
} S;

typedef struct t {
  S s;
}

T t = {0};
T *pointer_to_T = &t;


printf("End address %x", pointer_to_T->s);
printf("Beginning address %x", &(pointer_to_T->s));

Based on my testing, pointer_to_T->s is the address of the end of the structure S

pointer_to_T->s - &(pointer_to_T->s) = sizeof(S)

What is the expected behaviour here? Or is this just a coincidence?

Answer 1

The expected behaviour here can range from printing garbage to nasal demons , because this behaviour is undefined. The %x specifier makes printf expect an integer but it gets a struct, so anything is possible. What's most likely happening here is that it would print sx , but again it may as well spawn a one-way portal to Петропа́вловск-Камча́тский .

Answer 2

Structures element isnot a pointer. It won't print any address of the structure. That would be just garbage value which you are considering as end address. Garbage is undefined.

Structure elements are not pointer that way array is.

%x – Print a hexadecimal integer