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Definition: null

A character that is all 0 bits. Also written as "NUL," it is the first character in the ASCII and EBCDIC data codes. In hex, it displays and prints as 00; in decimal, it may appear as a single zero in a chart of codes, but displays and prints as a blank space.

Nulls are naturally found in binary numbers when a byte contains all zeros, and they are used to pad fields (see padding). A null may function as a delimiter; for example, in C/C++, a null character is inserted at the end of a character string to mark the end of the text.

The Null Is the First
Note the first character at the top of this chart of ASCII characters. The 00 means 0000-0000 bits.