C/C ++ Basic Data Type

Basic Type

The C/C ++ language has a set of basic types, which correspond to the basic storage units of computers and some common ways to use these units to save data:

The basic data types are as follows:

Name	Description	Size *	Range *
Char	Character or small integer.	1 byte	Signed:-128 to 127 Unsigned: 0-255
Short int(Short)	Short integer.	2 bytes	Signed:-32768 to 32767 Unsigned: 0-65535
Int	Integer.	4 bytes	Signed:-2147483648 to 2147483647 Unsigned: 0-4294967295
Long int(Long)	Long integer.	4 bytes	Signed:-2147483648 to 2147483647 Unsigned: 0-4294967295
Bool	Boolean value. It can take one of two values: true or false.	1 byte	TrueOrFalse
Float	Floating Point Number.	4 bytes	+/-3.4e +/-38 (~ 7 digits)
Double	Double Precision Floating Point Number.	8 bytes	+/-1.7e +/-308 (~ 15 digits)
Long double	Long Double Precision Floating Point Number.	8 bytes	+/-1.7e +/-308 (~ 15 digits)
Wchar_t	Wide character.	2Or4 bytes	1 wide character

In addition, you can also define:

Enumeration type of a group of specific values (Enum)

Type void, indicating no information

Pointer type, such as int *

Array type, such as char []

Reference type, such as double &

 

Declare Variables

 Int A;
 Float Mynumber;
 Const   Double Pi = 3.1415926 ;
 Extern   Int Error_number;

 Const   Char * Name = "  Blue  " ;
 Const   Char * Season [] = { "  Spring  " , "  Summer  " , "  Fall  " , " Winter  " };

Void cannot directly define a variable other

 
VoidAvoid;//Error! A variable cannot be directly defined for the void type.
 

Declare multiple names:

 
IntA, B, C;
Int* P, Y;//This structure is not conducive to reading and should be avoided as much as possible
IntV [10], * PV;//This structure is not conducive to reading and should be avoided as much as possible
 

  Initialize variable

The initialization variables are as follows:

 
Type identifier = initial_value;
 

For example, initialize an integer variable to 0, for example

 

 
IntA =0;
 

There is another form of initialization variable:

 

 
Type identifier (initial_value );
 

For example

 

 
IntA (0);