0o1045

0o1045 is an octal numeric literal used in several programming languages to denote a value written in base 8. The prefix 0o (zero-o) signals octal notation, and the digits that follow must be between 0 and 7.

Interpreting 0o1045 in base 8 yields decimal 549, calculated as 1×8^3 + 0×8^2 + 4×8 + 5 = 512 + 0 + 32 + 5 = 549. In hexadecimal form, the same value is 0x225 (549 decimal).

In Python 3, 0o1045 is a valid integer literal; Python 2 used a leading zero without the o prefix, which could lead to ambiguity during migration. Other languages, such as JavaScript (ECMAScript 2015 and later) and Ruby, also support the 0o prefix for octal literals. Some languages, like Go, use different conventions for octal representation, which can differ from the 0o style. Octal notation is often encountered in contexts such as Unix file permissions and various low-level data representations where bitwise grouping is convenient.

Caveats include ensuring digits are within the 0–7 range and recognizing that 8 or 9 cannot appear in an octal literal. When moving between languages, or when parsing numeric literals from strings, the presence or absence of an octal prefix can affect interpretation, so explicit base specification is important for correctness.