013-union, enumeration
Commonwealth (Consortium):
What is a consortium?
Similar to a structure, but the biggest difference lies in the allocation of storage space ;
The purpose is to define a union when the type of the target quantity is uncertain;
It can save space; The first name of all member variables in
the union Among the member variables of the union, generally only one member variable is used at the same time ;
What types can unions contain?
Basic data types:
char/short/int/long/float/double
Composite types:
Array-Integer array/character data,,,, Array of
pointers
Structure
Union (not the structure itself
) Structure Array
Pointer - Integer Pointer/Character Pointer,,,
Array Pointer/Function Pointer
Structure Pointer
Function?
can't
How is a union defined?
格式:
union 联合体类型名
{
...