1, There are four definitions of structure types and structure variables:

1. Define type structure type first, and then structure variable

struct stu
{
	int num;
	char *name;
};
void test()
{
	struct stu people;
}

2. Define variables when defining structure type

struct stu
{
	int num;
	char *name;
}xiao_ming, xiao_hong;

3. Type of disposable structure

struct
{
	int num;
	char *name;
}xiao_ming, xiao_hong;

4. You can define variables multiple times by aliasing one-time structures.

struct
{
	int num;
	char *name;
}STU;

2, Initialization of structure variables:

1. Define variables as initialization

struct stu
{
	int num;
	char *name;
};
void test()
{
	struct stu people = {10, "xiao_ming"};
}

2. Define variables and initialize at the same time when defining a structure

struct stu
{
	int num;
	char *name;
}xiao_ming = {10, "xiao_ming"}, xiao_hong = {20, "xiao_hong"};

3. Use memset to initialize the structure to 0

struct stu
{
	int num;
	char *name;
};
void test()
{
	struct stu people;
        memset(&people, 0, sizeof(people));
}

4. Member by member assignment

struct stu
{
	int num;
	char *name;
};
void test()
{
	struct stu people;
	people.num = 10;
	people.name = "xiao_ming";
}

3, Access to members:

1. Structure variable name. Member variable name
2. Structure address - > member variable name

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<string.h>


int main(int argc, char *argv[])
{
	struct stu tom = {10, "tom", 10.0f};
	struct stu *p = &tom;

	printf("num = %d, name = %s, score = %f\n", p->num, p->name, p->score);
	printf("num = %d, name = %s, score = %f\n", (*p).num, (*p).name, (*p).score);
	printf("num = %d, name = %s, score = %f\n", tom.num, tom.name, tom.score);
	printf("num = %d, name = %s, score = %f\n", (&tom)->num, (&tom)->name, (&tom)->score);


	system("pause");
	return 0;
}

Note 1:

1. Structure (object) members select the use point (variable name on the left).
2. Pointer members choose to use the pointing operator (address on the left).

Note 2:

1. The structure address is the same as the address of the first member variable. Unlike arrays, the variable name of a structure is not an address. You need to use the address character for the variable name.
2. Structure address - > member variable name < = = > member variable name < = = > * member variable address.
3. Just remember that the structure address can find the address of the member variable through - > (point operator), and directly operate the content corresponding to the address.