转msdn上的Data Type Ranges

最新推荐文章于 2020-03-13 23:08:27 发布

转载最新推荐文章于 2020-03-13 23:08:27 发布 · 787 阅读

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#preprocessor #compiler #character #integer #attributes #types

本文介绍了Microsoft Visual C++中各种数据类型的字节大小、别名及取值范围，包括整型、字符型、浮点型等基本类型及其变种。

Data Type Ranges

Microsoft Visual C++ recognizes the types shown in the table below.

Type Name	Bytes	Other Names	Range of Values
int	*	signed, signed int	System dependent
unsigned int	*	unsigned	System dependent
__int8	1	char, signed char	–128 to 127
__int16	2	short, short int, signed short int	–32,768 to 32,767
__int32	4	signed, signed int	–2,147,483,648 to 2,147,483,647
__int64	8	none	–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
bool	1	none	false or true
char	1	signed char	–128 to 127
unsigned char	1	none	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
long long	8	none (but equivalent to __int64)	–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
unsigned long	4	unsigned long int	0 to 4,294,967,295
enum	*	none	Same as int
float	4	none	3.4E +/- 38 (7 digits)
double	8	none	1.7E +/- 308 (15 digits)
long double	same as double	none	same as double
wchar_t	2	__wchar_t	0 to 65,535

A variable of __wchar_t designates a wide-character or multibyte character type. By default wchar_t is a typedef for unsigned short. Use the L prefix before a character or string constant to designate the wide-character-type constant. When compiling with /Zc:wchar_t or /Za, the compiler can distinguish between an unsigned short and wchar_t for function overload purposes.

Signed and unsigned are modifiers that can be used with any integral type except bool. The char type is signed by default, but you can specify /J (compiler option) to make it unsigned by default.

The int and unsigned int types have the size of the system word: four bytes. However, portable code should not depend on the size of int.

Microsoft C/C++ also features support for sized integer types. See __int8, __int16, __int32, __int64 for more information. Also see Integer Limits.

See Fundamental Types for more information on the restrictions of the sizes of each type.