struct-Body pointer

Use of pointer to struct type variable
Let's first define the structure:
struct STU
{
Char name[20];
Long number;
float score[4];
} ;
Then define a pointer variable that points to the struct type variable:
struct Stu *p1, *p2;
Define pointer variables p 1, p 2, pointing to struct type variables, respectively. The reference form is: pointer variable → member;
[Example 7-2] Correct use of a variable pointing to a struct type. enter a member of a struct type variable and output it.

#include <stdlib.h>/* Use M a l l o C () required */
struct Data/* define struct */
{
int day,month,year;
} ;
struct STU/* define struct body */
{
Char name[20];
Long num;
struct data birthday; /nested * Set of struct type members */
} ;
Main ()
{
struct Stu *student; Fixed//semantic struct type pointer */
Student=malloc (sizeof (struct stu)); Assign a secure address to/from the * PIN variable */
printf ("Input name,number,year,month,day:/n");
scanf ("%s", student->name); * * Enter student's name, school number, date of birth * *
scanf ("%ld", &student->num);
scanf ("%d%d%d", &student->birthday.year,&student->birthday.month,
&student->birthday.day);
printf ("/noutputname,number,year,month,day/n");
/* Print out values for each member item */
printf ("%20s%10ld%10d//%d//%d/n", Student->name,student->num,
Student->birthday.year,student->birthday.month,
Student->birthday.day);
}

Using struct type pointers in your program to refer to members of struct variables, you need to pass the function malloc () provided by C to
The pointer assigns a secure address. The function sizeof () returns a value that calculates the number of bytes of memory for a given data type. The pointer means
The Member forms are:

Student->name
Student->num
Student->birthday.year
Student->birthday.month
Student->birthday.day

Use of pointers to arrays of struct types
Defines an array of struct types whose array name is the first address of the array.
A pointer to a struct type that can point to an element of an array, or to an array, to be distinguished when used.
[Example 7-3] In example 7-2 defines the structure of the type, based on this type and then define the structure of the body array and pointer to the struct type .

struct data
{
Intday,month,year;
};
struct STU/* Define structure body */
{
Char name[20];
Long num;
struct data birthday;/The struct type member of the nested * set * *
};

struct stustudent[4],*p;///semantic struct array and pointer to struct type */
As P=student, the pointer p points to the struct array student.
P is a pointer to an array of one-dimensional structures that can be referenced in three ways.
1) Address law
Both Student+i and p+i represent the addresses of the element I elements of the array, and the members of the array elements are referenced in the following form:
(Student+i)->name, (Student+i)->num and (P+i)->name, (p+i)->num, etc. Student+i and P+i
Same as &student[i].
2) Pointer method
If p points to an element of an array, then p++ points to its subsequent elements.
3) array notation for pointers
If p=student, we say that pointer p to array student,p[i] represents the element I of the array, and its effect is
Student[i] equivalent. A reference to an array member is described as: P[i].name, P[i].num, and so on.
[Example 7-4] The use of pointer variables to a struct array.

structdata/* define struct type */
{
Intday,month,year;
};
structstu/* define struct type */
{
Char name[20];
Long num;
struct data birthday;
};
Main ()
{int i;
structstu*p,student[4]={{"Liying", 1,1978,5,23},{"wangping", 2,1979,3,14},
{"Libo", 3,1980,5,6},{"Xuyan", 4,1980,4,21}};
/* Define struct array and initialize */
P=student;/* assigns the first address of the array to the pointer p,p points to a one-dimensional array student*/
printf ("/n1----outputname,number,year,month,day/n");
for (i=0;i<4;i++)/* Use the pointer method to output the members of the array element */
printf ("%20s%10ld%10d//%d//%d/n", (P+i)->name, (p+i)->num,
(P+i)->birthday.year, (p+i)->birthday.month,
(p+i)->birthday.day);
}

struct-Body pointer