0b0001

0b0001 is a binary literal used in several programming languages to denote a binary value. The prefix 0b signals that the following digits are base-2. The four digits 0001 represent a pattern with only the least-significant bit set. Numerically, 0b0001 equals the decimal value 1, and in typical two's complement representations it encodes a positive one-bit pattern.

Language support for the 0b prefix varies. Languages such as Python, Java, JavaScript, and Go accept binary literals with the 0b prefix. In C and C++, binary literals are not part of the ISO standard, though many compilers provide the 0b form as an extension.

As with other integer literals, the type and width of 0b0001 depend on the language and any suffixes. In most contexts it denotes an integer value (often int or unsigned int), and the leading zeros mainly affect readability or documentation; they do not impose a fixed width at runtime unless the language defines a fixed-width type.

Common uses include bit masking and flag operations. For example, 0b0001 can enable the first flag, and combining literals such as 0b0001 | 0b0010 yields 0b0011. Checking a bit may involve tests like x & 0b0001 to determine whether the least-significant bit is set.