Fundamental types

 

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See this for the types supplied by the standard C++ library.

Boolean type

bool - type, capable of holding one of the two values: true or false.

Character types

signed char - type for signed character representation.

unsigned char - type for unsigned character representation.

char - type for character representation which can be most efficiently processed on the target system (equivalent to either signed char or unsigned char).

wchar_t - type for wide character representation

char16_t - type for UTF-16 character representation (since C++11)

char32_t - type for UTF-32 character representation (since C++11)

Integer types

int - basic integer type. Can be omitted if any of the modifiers are present. If no length modifiers are present, guaranteed to have width of at least 16 bits. However, on 32/64 bit systems it is almost exclusively guaranteed to have width of at least 32 bits (see below).

Modifiers

Modifies the integer type. Can be mixed in any order. Only one of each group can be present in type definition.

Signedness

signed - target type will have signed representation (this is the default if omitted)

unsigned - target type will have unsigned representation

Size

short - target type will be optimized for space and will have width of at least 16 bits.

long - target type will have width of at least 32 bits.

long long - target type will have width of at least 64 bits (since C++11)

Properties

The following table summarizes all available integer types and their properties:

Type specifier	Equivalent type	Width in bits by data model
		C++ standard	LP32	ILP32	LLP64	LP64
short	short int	at least 16	16	16	16	16
short int
signed short
signed short int
unsigned short	unsigned short int
unsigned short int
int	int	at least 16	16	32	32	32
signed
signed int
unsigned	unsigned int
unsigned int
long	long int	at least 32	32	32	32	64
long int
signed long
signed long int
unsigned long	unsigned long int
unsigned long int
long long	long long int (C++11)	at least 64	64	64	64	64
long long int
signed long long
signed long long int
unsigned long long	unsigned long long int (C++11)
unsigned long long int

Note: the C++ Standard guarantees that 1 == sizeof(char) <= sizeof(short) <= sizeof(int) <= sizeof(long) <= sizeof(long long).

Data models

32 bit systems:

• LP32:

• Win16 API

• ILP32;

• Win32 API
• Unix and Unix-like systems (Linux, Mac OS X)

64 bit systems:

• LLP64

• Win64 API

• LP64

• Unix and Unix-like systems (Linux, Mac OS X)

Floating point types

float - single precision floating point type. Usually IEEE-754 32 bit floating point type

double - double precision floating point type. Usually IEEE-754 64 bit floating point type

long double - extended precision floating point type. Does not necessarily map to types mandated by IEEE-754. Usually 80-bit x87 floating point type on x86 and x86-64 architectures.

Range of values

The following table provides a reference for limits of common numeric representations. Note, that all popular data models (including all of ILP32, LP32, LP64, LLP64) use two's complement arithmetic. Also, the C++ Standard does not specify which arithmetic would be used, thus it guarantees only the limits of one's complement arithmetic.

Type	Size in bits	Format	Value range
			Approximate	Exact
character	8	signed (one's complement)	-127 to 127
		signed (two's complement)	-128 to 127
		unsigned	0 to 255
integral	16	signed (one's complement)	± 3.27 · 104	-32767 to 32767
		signed (two's complement)		-32768 to 32767
		unsigned	0 to 6.55 · 104	0 to 65535
	32	signed (one's complement)	± 2.14 · 109	-2,147,483,647 to 2,147,483,647
		signed (two's complement)		-2,147,483,648 to 2,147,483,647
		unsigned	0 to 4.29 · 109	0 to 4,294,967,295
	64	signed (one's complement)	± 9.22 · 1018	-9,223,372,036,854,775,807 to 9,223,372,036,854,775,807
		signed (two's complement)		-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
		unsigned	0 to 1.84 · 1019	0 to 18,446,744,073,709,551,615
floating point	32	IEEE-754	± 3.4 · 10± 38 (~7 digits)	min subnormal: ± 1.401,298,4 · 10-47 min normal: ± 1.175,494,3 · 10-38 max: ± 3.402,823,4 · 1038
	64	IEEE-754	± 1.7 · 10± 308 (~15 digits)	min subnormal: ± 4.940,656,458,412 · 10-324 min normal: ± 2.225,073,858,507,201,4 · 10-308 max: ± 1.797,693,134,862,315,7 · 10308

Keywords

bool, true, false, char, wchar_t, char16_t, char32_t, int, short, long, signed, unsigned, float, double

See also

• cv specifiers,
• storage duration specifiers