# C Integer Constants

Visual Studio 2015

For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.

An "integer constant" is a decimal (base 10), octal (base 8), or hexadecimal (base 16) number that represents an integral value. Use integer constants to represent integer values that cannot be changed.

## Syntax

integer-constant:
decimal-constant integer-suffix opt

octal-constant integer-suffix opt

decimal-constant:
nonzero-digit

decimal-constant digit

octal-constant:
0

octal-constant octal-digit

nonzero-digit: one of
1 2 3 4 5 6 7 8 9

octal-digit: one of
0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7 8 9

a b c d e f

A B C D E F

integer-suffix:
unsigned-suffix long-suffix opt

long-suffix unsigned-suffix opt

unsigned-suffix: one of
u U

long-suffix: one of
l L

64-bit integer-suffix:
i64

Integer constants are positive unless they are preceded by a minus sign (). The minus sign is interpreted as the unary arithmetic negation operator. (See Unary Arithmetic Operators for information about this operator.)

If an integer constant begins with 0x or 0X, it is hexadecimal. If it begins with the digit 0, it is octal. Otherwise, it is assumed to be decimal.

The following lines are equivalent:

```0x1C   /* = Hexadecimal representation for decimal 28 */
034    /* = Octal representation for decimal 28 */

```

No white-space characters can separate the digits of an integer constant. These examples show valid decimal, octal, and hexadecimal constants.

```/* Decimal Constants */
10
132
32179

/* Octal Constants */
012
0204
076663