Bc Programming Language
bc, for basic calculator, is "an arbitrary precision calculator language" with syntax similar to the C programming language. bc is typically used as either a mathematical scripting language or as an interactive mathematical shell.
A typical interactive usage is typing the command bc on a Unix command prompt and entering a mathematical expression, such as (1 + 3) * 2, whereupon 8 will be output. While bc can work with arbitrary precision, it actually defaults to zero digits after the decimal point - so the expression 2/3 yields 0. This can surprise new bc users unaware of this fact. The "-l" option to bc sets the default scale (digits after the decimal point) to 20, and adds several additional mathematical functions to the language.
Bc first appeared in Version 6 Unix in 1975, and was written by Robert Morris and Lorinda Cherry of Bell Labs. Bc was preceded by dc, an earlier arbitrary precision calculator written by the same authors. Dc could do arbitrary-precision calculations, but its reverse polish notation syntax was inconvenient for users, and therefore Bc was written as a front-end to Dc. Bc was a very simple compiler (a single yacc source file with a few hundred lines) which converted the new, C-like, bc syntax into dc's reverse polish notation, and piped the results through dc.
In 1991, POSIX rigorously defined and standardized bc. Two implementations of this standard survive today: The first is the traditional Unix implementation, a front-end to dc, which survives in Unix and Plan 9 systems. The second is the free software GNU bc, first released in 1991 by Philip A. Nelson. The GNU implementation has numerous extensions beyond the POSIX standard, and is no longer a front-end to dc (it is a bytecode interpreter).
Read more about Bc Programming Language: POSIX Bc, Plan 9 Bc, GNU Bc, Example Code, Calculating Pi To 10000 Places, A Translated C Function, Using Bc in Shell Scripts
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