C如何访问结构中的结构成员？

Question

I have a struct that has a struct as a member, and I want to access that member from the first struct. You didn't get it? I will show you.

typedef struct 
{
    int day;
} Date;

typedef struct 
{
    struct Date;
} Insert;

Insert insert;

scanf("%d", &insert.day); // I tried this but it doesn't work
scanf("%d", &insert.date.day); // Figured maybe this would do it, but nope

Answer 1

You need :

typedef struct 
{
    Date date;
} Insert;

Insert insert;

Then,

scanf("%d", &insert.date.day);

Answer 2

As others have said , the way you have your code written, it will not build. You should get an error where indicated in the following:

typedef struct 
{
    int day;
} Date;

typedef struct 
{
    struct Date;//Error here - Undefined size for field, incomplete struct Date defined at cfile.c:8
} Insert;

Insert insert;

int main(void)
{
    return 0;   
}

You have already created a type Date (ie typedef struct ... Date ), use it instead of struct Date; like this: (this will build)

#include <ansi_c.h>
typedef struct 
{
    int day;
} Date;//you have just created a new type:  struct Date here..., use "Date date;" below, (not struct Date;)

typedef struct 
{
    Date date;//"Date is a type (typedef struct Date), so use it here to declare the member "date"
} Insert;

Insert insert;

int main(void)
{
    return 0;   
}  

int main(void)
{
      scanf("%d", &insert.date.day);
      return 0; 
}