Editing C syntax (section)

====Backslash escapes====
{{main|Escape sequences in C}}
Because certain characters cannot be part of a literal string expression directly, they are instead identified by an escape sequence starting with a backslash ({{code|\}}). For example, the backslashes in {{code|"This string contains \"double quotes\"."}} indicate (to the compiler) that the inner pair of quotes are intended as an actual part of the string, rather than the default reading as a delimiter (endpoint) of the string itself.

Backslashes may be used to enter various control characters, etc., into a string:
{| class="wikitable"
! align="left" |Escape
! align="left" |Meaning
|-
| {{code|\\}} || Literal backslash
|-
| {{code|\"}} || Double quote
|-
| {{code|\'}} || Single quote
|-
| {{code|\n}} || Newline (line feed)
|-
| {{code|\r}} || Carriage return
|-
| {{code|\b}} || Backspace
|-
| {{code|\t}} || Horizontal tab
|-
| {{code|\f}} || Form feed
|-
| {{code|\a}} || Alert (bell)
|-
| {{code|\v}} || Vertical tab
|-
| {{code|\?}} || Question mark (used to escape [[C trigraph|trigraphs]], obsolete feature dropped in C23)
|-
| <code>\''OOO''</code> || Character with octal value ''OOO'' (where ''OOO'' is 1-3 octal digits, '0'-'7')
|-
| <code>\x''hh''</code> || Character with hexadecimal value ''hh'' (where ''hh'' is 1 or more hex digits, '0'-'9','A'-'F','a'-'f')
|-
| <code>\u''hhhh''</code> || [[Unicode]] [[code point]] below 10000 hexadecimal (added in C99)
|-
| <code>\U''hhhhhhhh''</code> || Unicode code point where ''hhhhhhhh'' is eight hexadecimal digits (added in C99)
|}

The use of other backslash escapes is not defined by the C standard, although compiler vendors often provide additional escape codes as language extensions. One of these is the escape sequence <code>\e</code> for the [[escape character]] with ASCII hex value 1B which was not added to the C standard due to lacking representation in other [[character set]]s (such as [[EBCDIC]]). It is available in [[GNU Compiler Collection|GCC]], [[clang]] and [[Tiny C Compiler|tcc]].

Note that [[printf format string]]s use {{code|%%}} to represent literal {{code|%}} character; there is no {{code|\%}} escape sequence in standard C.