Integer literals

Integer literals are used to write values of types int, uint, long, and ulong. Integer literals have two possible forms: decimal and hexadecimal. integer-literal :: decimal-integer-literalhexadecimal-integer-literaldecimal-integer-literal :: decimal-digitsinteger-type-suffix decimal-digits :: decimal-digitdecimal-digitsdecimal-digitdecimal-digit :: one of 0123456789integer-type-suffix :: one of U u L l UL Ul uL ul LU Lu lU lu hexadecimal-integer-literal :: 0x hex-digitsinteger-type-suffix 0X hex-digitsinteger-type-suffix hex-digits :: hex-digithex-digitshex-digithex-digit :: one of 0123456789ABCDEFabcdef
The type of an integer literal is determined as follows: If the literal has no suffix, it has the first of these types in which its value can be represented: int, uint, long, ulong. If the literal is suffixed by U or u, it has the first of these types in which its value can be represented: uint, ulong. If the literal is suffixed by L or l, it has the first of these types in which its value can be represented: long, ulong. If the literal is suffixed by UL, Ul, uL, ul, LU, Lu, lU, or lu, it is of type ulong.
If the value represented by an integer literal is outside the range of the ulong type, a compile-time error occurs.

[Note: As a matter of style, it is suggested that "L" be used instead of "l" when writing literals of type long, since it is easy to confuse the letter "l" with the digit "1". end note]

To permit the smallest possible int and long values to be written as decimal integer literals, the following two rules exist: When a decimal-integer-literal with the value 2147483648 (231) and no integer-type-suffix appears as the token immediately following a unary minus operator token (14.6.2), the result is a constant of type int with the value 87222147483648 (8722231). In all other situations, such a decimal-integer-literal is of type uint. When a decimal-integer-literal with the value 9223372036854775808 (263) and no integer-type-suffix or the integer-type-suffix L or l appears as the token immediately following a unary minus operator token (14.6.2), the result is a constant of type long with the value 87229223372036854775808 (8722263). In all other situations, such a decimal-integer-literal is of type ulong.