Punch in: 4.23 C language chapter - (1) first knowledge of C language - (12) structure

Structure

The structure is C Especially important knowledge points in language , The structure makes C Language has the ability to describe complex types .

For example, describe students , Students include ： name + Age + Gender + Student number These information .
Describe a Book , This book includes ： Title + Press. + Catalog + Author, etc
These are complex objects ,C Language gives you the ability to customize types
One of the custom types is called ： Structure struct

Structure is the practice of combining some single types

for example , Let's now describe a person , He has a name + Age + Gender + Student number These information

struct Stu
{
    
    char name[20];// name 
    int age;      // Age 
    char sex[5];  // Gender 
    char id[15]; // Student number 
};

int main()
{
    

return 0;
}

We're going to build a house ,struct Stu It's our drawing , Create a structure object s, Fill in the data according to the drawing

Initialization of structure

// Print structure information 
struct Stu s = {
    " Zhang San ", 20, " male ", "20180101"};

You can put struct Stu As a data type ,s Is to create a to store data Structure object ,s The data in it is Member name stay struct Stu When not in use , Those types inside won't open up space

Print

//. Access operators for structure members 
printf("name = %s age = %d sex = %s id = %s\n", s.name, s.age, s.sex, s.id);

To print s The message inside , To print in the order of types ," Zhang San ", 20, " male ", "20180101" Corresponding %s,%d,%s,%s, The order cannot be reversed , And in accordance with Structure object . Member name In the form of

There's another way to print

//
struct Stu *ps = &s;
printf("name = %s age = %d sex = %s id = %s\n", (*ps).name, (*ps).age, (*ps).sex, (*ps).id);

ps Is a struct pointer variable , Here is the method of pointer there , But it's a bit of a hassle , It can be used directly -> The operator

struct Stu *ps = &s;
printf("name = %s age = %d sex = %s id = %s\n", ps->name, ps->age, ps->sex, ps-
>id);

ps->name It means ps Point to s Members of the name, and (*ps).name It means the same thing