ASCII 48 — 0

Zero is the additive identity in mathematics and a pivotal concept in the history of human thought, independently discovered by the Maya, Indian, and Babylonian civilizations. In programming, zero serves as the falsy value, the starting array index in most languages, and the basis for null pointer representations. The digit character '0' (ASCII 48) is distinct from the NUL control character (ASCII 0) — confusing the character with the code point value is a common beginner mistake in systems programming.

The ten decimal digit characters (0–9) occupy consecutive ASCII codes 48 through 57, arranged sequentially by deliberate design. This placement enables the classic parsing technique of subtracting the character '0' (code 48) from any digit character to yield its integer value — a trick embedded in virtually every text processing system and parser written in the past six decades. Digit characters are fundamentally distinct from numeric values: the character '5' is stored as byte value 53, not the integer 5.

In the ASCII encoding table, Digit 0 is assigned code point 48 in decimal (0x30 hexadecimal, 060 octal, 00110000 binary). The 7-bit ASCII standard, first published in 1963 by the American Standards Association, defines exactly 128 characters that remain the foundation of text encoding systems worldwide. UTF-8, the dominant encoding on the modern web, is fully backward compatible with ASCII — every ASCII character is encoded as the identical single byte in UTF-8, guaranteeing that Digit 0 works reliably across all operating systems, programming languages, and internet protocols.