in a readable fashion. There are four major C indent styles,
described below; all have the aim of making it easier for the
reader to visually track the scope of control constructs. The
significant variable is the placement of `{' and `}'
with respect to the statement(s) they enclose and to the guard or
controlling statement (`if', `else', `for',
`while', or `do') on the block, if any.
`K&R style' --- Named after Kernighan & Ritchie, because the
examples in K&R are formatted this way. Also called `kernel
style' because the UNIX kernel is written in it, and the `One True
Brace Style' (abbrev. 1TBS) by its partisans. The basic indent
shown here is eight spaces (or one tab) per level; four spaces are
occasionally seen, but are much less common.
if (cond) {
<body>
}
`Allman style' --- Named for Eric Allman, a Berkeley hacker who
wrote a lot of the BSD utilities in it (it is sometimes called
`BSD style'). Resembles normal indent style in Pascal and
Algol. Basic indent per level shown here is eight spaces, but four
spaces are just as common (esp. in C++ code).
if (cond)
{
<body>
}
`Whitesmiths style' --- popularized by the examples that came
with Whitesmiths C, an early commercial C compiler. Basic indent
per level shown here is eight spaces, but four spaces are
occasionally seen.
if (cond)
{
<body>
}
`GNU style' --- Used throughout GNU EMACS and the Free Software
Foundation code, and just about nowhere else. Indents are always
four spaces per level, with `{' and `}' halfway between the
outer and inner indent levels.
if (cond)
{
<body>
}
Surveys have shown the Allman and Whitesmiths styles to be the most
common, with about equal mind shares. K&R/1TBS used to be nearly
universal, but is now much less common (the opening brace tends to
get lost against the right paren of the guard part in an `if'
or `while', which is a Bad Thing). Defenders of 1TBS
argue that any putative gain in readability is less important than
their style's relative economy with vertical space, which enables
one to see more code on one's screen at once. Doubtless these
issues will continue to be the subject of holy wars.