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== History ==
Circa 1969, Ken Thompson<ref name=chist /> and later Dennis Ritchie<ref name=bur /> developed B basing it mainly on the [[BCPL]] language Thompson used in the [[Multics]] project. B was essentially the BCPL system stripped of any component Thompson felt he could do without in order to make it fit within the memory capacity of the minicomputers of the time. The BCPL to B transition also included changes made to suit Thompson's preferences (mostly along the lines of reducing the number of non-whitespace characters in a typical program).<ref name=chist /> Much of the typical [[ALGOL]]-like syntax of BCPL was rather heavily changed in this process. The assignment operator <code>:=</code>
Thompson added "two-address assignment operators" using <code>x =+ y</code> syntax to add y to x (in C the operator is written <code>+=</code>). This syntax came from [[Douglas McIlroy]]'s implementation of [[TMG (language)|TMG]], in which B's compiler was first implemented (and it came to TMG from [[ALGOL 68]]'s <code>x +:= y</code> syntax).<ref name=chist /><ref>{{cite web |author=Michael S. Mahoney |author-link=Michael Sean Mahoney |url=https://www.princeton.edu/~hos/mike/transcripts/mcilroy.htm |title=Interview with M.D. McIlroy |___location=Murray Hill |date=18 August 1989|website=Princeton.edu}}</ref> Thompson went further by inventing the increment and decrement operators (<code>++</code> and <code>--</code>). Their prefix or postfix position determines whether the value is taken before or after alteration of the operand. This innovation was not in the earliest versions of B. According to Dennis Ritchie, people often assumed that they were created for the auto-increment and auto-decrement address modes of the DEC PDP-11, but this is historically impossible as the machine didn't exist when B was first developed.<ref name=chist />
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