C + + Primer notes-Basic built-in types

1. The arithmetic types are divided into two categories: integer and floating-point. The size of the arithmetic type differs on different machines, and the following table lists the minimum values for the dimensions specified by the C + + standard. It also allows the compiler to give these types a larger size.

A char is the same size as a machine byte.

An int is at least as big as a short;

A long is at least as large as an int;

A long long is at least as large as a long;

The following excerpt from MSDN:

category	type	content
Integer	char	chara type is an integer type that typically contains a member of the basic execution character set-by default, this is ASCII in Microsoft C + +. The C + + compiler treats char signed char unsigned char variables of type, and types as different types. charvariables of type will be promoted as if int they were types by default signed char , unless the/j compilation option is used. In this case, they are treated as unsigned char types and promoted to int (no symbol extension).
	bool	boolA type is an true integer type that can have or false one of these two values. Its size is not specified.
	short	shortinttype (or short ) is an integral type that is greater than or equal to the size of the char type but less than or equal to the size of the int type. shortobject of type can be declared as signed short or unsigned short . Signed shortis short synonymous with.
	int	intType is an integer type greater than or equal to the size of the short int type but less than or equal to the size of the long type. intobject of type can be declared as signed int or unsigned int . Signed int is int synonymous with.
	__int8, __int16, __int32, __int64,__int128	A fixed-size integer __int``n that n is the size (in bits) of the integer variable. (,,,, __int8 __int16 __int32 __int64 and __int128 are Microsoft-specific keywords.) Not all types are available on all architectures. ）
	long	longThe type (or long int ) is an integer type that is greater than or equal to the int size of the type. longobject of type can be declared as signed long or unsigned long . Signed long is long synonymous with.
	longlong	is greater than unsigned long . long longobject of type can be declared as signed long long or unsigned long long . Signed long long is long long synonymous with.
	wchar_t,__wchar_t	wchar_tA variable of type specifies a wide character or multibyte character type. By default, wchar_t this is a native type, but you can use/zc:wchar_t-to make a wchar_t unsigned short typedef. The __wchar_t type is a wchar_t Microsoft-specific synonym for the native type. Use the L prefix before a character or string literal to specify a wide character type.
Floating point	float	floatType is the smallest floating-point type.
	double	doubleA type is a floating-point type that is greater than or equal to the size of the float type but less than or equal to the long double type. Microsoft private: long double and double the representations are identical. But, long double and double are different types.
	long double	longdoubletype is a double floating-point type greater than or equal to the type.

Microsoft-Only

The following table lists the amount of storage required for the underlying types in Microsoft C + +.

type	size
bool, char, unsigned char, signed char,__int8	1 bytes
__int16, short, unsigned short, wchar_t,__wchar_t	2 bytes
float, __int32, int, unsigned int, long,unsigned long	4 bytes
double, __int64, long double,long long	8 bytes
__int128	16 bytes

The ranges specified in the following table contain both a start value and an end value.

type name	bytes	Other Name	range of Values
Int	4	Signed	–2,147,483,648 to 2,147,483,647
unsigned int	4	Unsigned	0 to 4,294,967,295
__int8	1	Char	–128 to 127
unsigned __int8	1	unsigned char	0 to 255
__int16	2	short, short int, signed short int	–32,768 to 32,767
unsigned __int16	2	unsigned short, unsigned short int	0 to 65,535
__int32	4	Signed, signed int, int	–2,147,483,648 to 2,147,483,647
unsigned __int32	4	unsigned, unsigned int	0 to 4,294,967,295
__int64	8	Long long, signed long long	–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
unsigned __int64	8	unsigned long long	0 to 18,446,744,073,709,551,615
bool	1	No	False or True
Char	1	No	128 to 127 (default) 0 to 255 (when compiling with/j)
Signed Char	1	No	–128 to 127
unsigned char	1	No	0 to 255
Short	2	short int, signed short int	–32,768 to 32,767
unsigned short	2	unsigned short int	0 to 65,535
Long	4	Long int, signed long int	–2,147,483,648 to 2,147,483,647
unsigned long	4	unsigned long int	0 to 4,294,967,295
Long Long	8	None (equivalent to __int64)	–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
unsigned long long	8	None (equivalent to unsigned __int64)	0 to 18,446,744,073,709,551,615
Enum	Varies	No	See remarks later in this article
Float	4	No	3.4E +/-38 (7-digit)
Double	8	No	1.7E +/-308 (15-digit)
Long double	Same as Double	No	Same as Double
wchar_t	2	__wchar_t	0 to 65,535

2. When we assign an unsigned type to a value that is outside its range, the result is the remainder of the initial value that represents the total number of numeric values for the unsigned type. When we assign a symbol type to a value that exceeds the range it represents, the result is undefined.

3. When an arithmetic expression has both an unsigned number and an int value, the int value is converted to the unsigned number.

4. Integers starting with 0 represent octal, representing hexadecimal numbers beginning with 0x 0X.

5. Specify the type of literal value.

C + + Primer notes-Basic built-in types