C/C ++ Basic Data Type

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

Void avoid; // error! A variable cannot be directly defined for the void type.

Declare multiple names:

Int a, B, c;
Int * p, y; // This structure is not conducive to reading, should be avoided as much as possible
Int v [10], * pv; // This structure is not conducive to reading, 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

 

int a = 0;

There is another form of initialization variable:

 

type identifier (initial_value) ; 

For example

 

int a (0);