Hexadecimal why 0x

Create a free Team What is Teams? Learn more. Ask Question. Asked 1 year, 2 months ago. Active 1 year, 2 months ago. Viewed 5k times. Where and when was this 0x prefix first used? Improve this question. V7 Unix seems to mark their first appearance in the Unix C compiler -- both the original C compiler and the new, portable, pcc. Sorry, couldn't resist — Pete Becker. PeteBecker Yes. Binary can only be one digit. PeteBecker But then again, binary too is as well only a single digit.

Every power of two needs in binary only a single digit Show 2 more comments. Active Oldest Votes. The prefix 0x identifies the number that follows as a hexadecimal constant, and the prefix 0 as an octal number base 8. Toggle navigation. What does "0x" mean in hexadecimal numbers?

Track My Order. Frequently Asked Questions. International Shipping Info. Send Email. Mon-Fri, 9am to 12pm and 1pm to 5pm U. Mountain Time:. This is the binary number system.

Binary numbers are usually prefixed with the '0b' characters which are not part of the number. Sometimes they are also subdivided into groups of 4 digits to make them easier to read as well as easier to relate to the hexadecimal number system. An example of a binary number is 0b The periods in the number don't represent anything, they just make it easier to read the number.

The binary system is simple to understand, but it takes a lot of digits to use the binary system to represent large numbers. The hexadecimal system can represent much larger numbers using fewer characters, and it closely resembles binary numbers.

Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search. Why are hexadecimal numbers prefixed as 0x? I understand the usage of the prefix but I don't understand the significance of why 0x was chosen. Something is still needed to specify the number base: the x is an arbitrary choice. The BCPL language used the syntax 8 for octal numbers. This is great because.

When C was created from B, the need for hexadecimal numbers arose the PDP had bit words and all of the points above were still valid. Since octals were still needed for other machines, 0x was arbitrarily chosen 00 was probably ruled out as awkward.

Imagine needing to come up with a system to denote hexadecimal numbers, and note we're working in a C style environment. How about ending with h like assembly? Unfortunately you can't - it would allow you to make tokens which are valid identifiers eg.

In the end, for whatever reason, they decided to put an x after a leading 0 to denote hexadecimal. It is unambiguous since it still starts with a number character so can't be a valid identifier, and is probably based off the octal convention of a leading 0. It's a prefix to indicate the number is in hexadecimal rather than in some other base.

The C programming language uses it to tell compiler. When compiler reads 0x , It understands the number is hexadecimal with the help of 0x term.

Usually we can understand by 16 or 8 or whatever.. I don't know the historical reasons behind 0x as a prefix to denote hexadecimal numbers - as it certainly could have taken many forms. This particular prefix style is from the early days of computer science.

However, for programming purposes we often need to distinguish the bases from binary base-2 , octal base-8 , decimal base and hexadecimal base - as the most commonly used number bases. At this point in time it is a convention used to denote the base of a number. I've written the number 29 in all of the above bases with their prefixes:.

Basically, an alphabet we most commonly associate with a base e. This is especially helpful because smaller numbers can confusingly appear the same in all the bases: 0b1, 0o1, 0d1, 0x1.

If you were using a rich text editor though, you could alternatively use subscript to denote bases: 1 2 , 1 8 , 1 10 , 1