0x000xFF

0x000xFF is a string that is generally not a valid hexadecimal literal in common programming languages. It often appears as a typographical error or a misformatted attempt to express two hexadecimal values in succession, namely 0x000 and 0xFF, with an extra x inserted between them.

In languages such as C, C++, JavaScript, and Python, a hexadecimal literal must begin with 0x (or 0X) and be followed by a contiguous sequence of hexadecimal digits (0-9, a-f, A-F). The sequence 0x000xFF breaks this rule because the second x is not a hexadecimal digit, and the entire token would not be recognized as a valid single literal. Lexers typically tokenize 0x000 as a valid literal, leaving xFF as an invalid token and producing a syntax error.

Possible interpretations include treating it as a typo for a single value such as 0x0000FF (a common 24-bit or 16-bit color or memory byte value) or as two adjacent byte values (0x00 and 0xFF) written without a proper operator. In data formats and source code, such a string can indicate corruption, a copy-paste mistake, or obfuscated text. In contexts like color codes, hexadecimal colors are usually written as 0xRRGGBB or as CSS-style #RRGGBB rather than 0x000xFF.

How to fix typically involves restoring a valid form based on intent. For a single value, use a contiguous literal such as 0x00FF or 0x0000FF. For two bytes, express them with a shift and bitwise OR (0x00 << 8) | 0xFF, or separate constants as appropriate.

See also: Hexadecimal, Hexadecimal literals, Tokenization, Lexical analysis.