1. struct structure
The basic syntax
struct myabc{
unsigned int a;
unsigned int b;
unsigned int c;
unsigned int d;
}
transfer:
int i;
struct myabc mybuf; // mybuf type is myabc
The number of structures is associated with some packaged as a whole, easy to use. Here I am in the course of work in a very complex project, to see the most is the structure of the body.
Its memory size and the memory occupied by its members.
2. union union
The use of union with struct keyword similar. Which is a common start address.
union myabc{
char a ;
int b;
double exp;
}
3. enum enumeration (collection)
Enumeration enum {name list of constants};
enum week {
Monday = 0, Tuesday = 1, Wednesday = 2, Thursday, Friday, Saturday, Sunday
};
4. typedef alias data type
int a; // a is a variable of type int
typedef int a; // a nickname is an int
A data type already exists an alias.
For example
typedef char char_t;
typedef signed char int8_t;
typedef double float64_t;