The "0b" is a prefix to denote that the number is in binary. A similar thing is done in hexadecimal where numbers start with "0x".

Other uses Zero-based budgeting, a technique of planning and decision-making which reverses the working process of traditional budgeting Blue Air (former IATA code: 0B), a former Romanian low-cost airline Turret 0B, a point on Hadrian's Wall associated with Milecastle 0

0b (or 0B) denotes a binary literal. C++ has allowed it since C++14. (It's not part of the C standard yet although some compilers allow it as an extension.) 0x (or 0X) is for hexadecimal. 0 can be used to denote an octal literal. (Interestingly 0 itself is an octal literal).

0b Translingual Etymology Coined by analogy with 0x by replacing x for hexadecimal with b for binary. C did not originally support the 0b prefix.

Binary (0b) and Hexadecimal (0x) Literals ¶ Binary is a base-2 numbering system (digits are either 0 or 1), while hexadecimal is a base-16 numbering system (digits 0-F).

Provided to YouTube by TuneCore 0B · Marabs & Carti 0B ℗ 2026 Esprit Records Released on: 2026-06-19 Artist: Marabs & Carti Performer: Marabs & Carti Rap: Marabs & Carti Vocals: Marabs & Carti...

In this video we will be looking at the mysterious '0b' prefix in C. The mystery is that this was not part of the original K&R C definition.

To specify a binary literal, add the prefix 0b or 0B to the number. The following examples show binary literals: ... Binary literals can make relationships among data more apparent than they would be in hexadecimal or octal. For example, each successive number in the following array is rotated by one bit:

Integer constants can be written as binary constants, consisting of a sequence of ‘ 0 ’ and ‘ 1 ’ digits, prefixed by ‘ 0b ’ or ‘ 0B ’. This is particularly useful in environments that operate a lot on the bit level (like microcontrollers).

What is the "0b" prefix? To prevent confusion, when writing a binary number, it may have a "0b" (zero and b) prefix. For example, 0b0100 represents "0100" in binary. By using this prefix, the reader knows this is not "100" in decimal. Binary humor The image is an example of some binary humor (joke) via a famous saying on many geek t-shirts.