C Now
Literal Constants
November 25, 1999

---

C Literal Constants

Type	Base	Example	Description
char *	character	"hello"	Any string of characters enclosed in double quotes (") (see Note 1)
int	character	'1'	Any single character in single quotes (')
	octal	01	Any octal number (digits 0-7) beginning with a 0 (zero)
	decimal	1	Any number (digits 0-9) not beginning with a 0 (zero)
	hexadecimal	0x1L	0X (zero X) or 0x (zero x) followed by any hexadecimal number (digits 0-F)
unsigned	octal	01U	Any octal number (digits 0-7) beginning with a 0 (zero) and followed by U or u
	decimal	1U	Any number (digits 0-9) not beginning with a 0 (zero) and followed by U or u
	hexadecimal	0x1U	0X (zero X) or 0x (zero x) followed by any hexadecimal number (digits 0-F) followed by U or u
long	octal	01L	Any octal number (digits 0-7) beginning with a 0 (zero) and followed by L or l
	decimal	1L	Any number (digits 0-9) not beginning with a 0 (zero) and followed by L or l
	hexadecimal	0x1L	0X (zero X) or 0x (zero x) followed by any hexadeciaml number (digits 0-F) followed by L or l
unsigned long	octal	01UL	Any octal number (digits 0-7) beginning with a 0 (zero) and followed by U or u and L or l
	decimal	1UL	Any number (digits 0-9) not beginning with a 0 (zero) and followed by U or u and L or l
	hexadecimal	0x1UL	0X (zero X) or 0x (zero x) followed by any hexadeciaml number (digits 0-F) followed by U or u and L or l
float	decimal	12.3	Any number (digits 0-9) containing a decimal point (.)
	decimal	12E1	Any number (digits 0-9) followed by E or e and followed by an exponent of 10 (12E1 = 12 * 101 = 120.)

---

Escape Sequences (see Note 2)

Code	Character	Description
\a	BEL	Audible alert
\b	BS	Backspace
\f	FF	Form Feed
\n	LF	New Line
\r	CR	Carriage Return
\t	HT	Horizontal Tab
\v	VT	Vertical Tab
\\	\	Backslash
\'	'	Single Quote
\"	"	Double Quote
\0	NULL	Binary zero
\nnn	Any	Three octal (0-7) digits following the backslash are interpreted as an octal number and stored in a single byte.
\xnn	Any	Two hexadecimal (0-F) digits following the backslash x are interpreted as a hexadecimal number and stored in a single byte.

---

Notes:

1. String constants are stored as the literal characters followed by a byte of binary 0.  The value returned is a pointer to the first character.
2. Escape sequences are coded within a character constant or a string constant, to represent non-printable and certain printable characters.  They are stored as a single character.

---