struct tag { 
    member-list；
    member-list；
    member-list；  
    ...
} variable-list;

typedef struct
{
    int a;
    char b;
    double c; 
} Simple_t;
Simple_t u1, u2[20], *u3;

//此結(jié)構(gòu)體的聲明包含了指向自己類型的指針
struct NODE
{
    char string[100];
    struct NODE *next_node;
};

struct B;    //對(duì)結(jié)構(gòu)體B進(jìn)行不完整聲明
//結(jié)構(gòu)體A中包含指向結(jié)構(gòu)體B的指針
struct A
{
    struct B *partner;
    //other members;
};
//結(jié)構(gòu)體B中包含指向結(jié)構(gòu)體A的指針，在A聲明完后，B也隨之進(jìn)行聲明
struct B
{
    struct A *partner;
    //other members;
};

struct Student{         //聲明結(jié)構(gòu)體
    char name[20];      //姓名
    int num;            //學(xué)號(hào)
    float score;        //成績(jī)
};

struct Student student1；

struct Student{         //聲明結(jié)構(gòu)體
    char name[20];      //姓名
    int num;            //學(xué)號(hào)
    float score;        //成績(jī)
}student1;

struct Books
{
   char  title[50];
   char  author[50];
   char  subject[100];
   int   book_id;
} book = {"C 語言", "RUNOOB", "編程語言", 123456};

# include <stdio.h>
struct AGE
{
    int year;
    int month;
    int day;
};
struct STUDENT
{
    char name[20];
    int num;
    struct AGE birthday;
    float score;
};
int main(void)
{
    struct STUDENT student1 = {"小明", 1207041, {1989, 3, 29}, 100};
    return 0;
}

 struct STUDENT student1; 
 student1.num = 1207041;

struct book gift = 
{ 
     .value = 25.99,
     .author = "James Broadfool",
     .title = "Rue for the Toad"
};