character literal

 

C++

Language

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Concepts library (C++20)

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Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

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Technical Specifications

 

C++ language

General topics
Preprocessor Comments	Keywords Escape sequences
Flow control
Conditional execution statements
if	switch
Iteration statements (loops)
for range-for (C++11)	while do-while
Jump statements
continue - break	goto - return
Functions
Function declaration
Lambda function declaration
inline specifier
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noexcept specifier (C++11)
Exceptions
throw-expression	try-catch block
Namespaces
Namespace declaration	Namespace aliases
Types
Fundamental types Enumeration types Function types	Compound types Union types
Specifiers
decltype (C++11) auto (C++11) alignas (C++11)	const/volatile constexpr (C++11)
Storage duration specifiers
Initialization
Default initialization Value initialization Zero initialization Copy initialization Direct initialization	Aggregate initialization List initialization (C++11) Constant initialization Reference initialization

Expressions
Value categories Order of evaluation	Operators Operator precedence
Alternative representations
Literals
Boolean - Integer - Floating-point
Character - String - nullptr (C++11)
User-defined (C++11)
Utilities
Attributes (C++11)
Types
typedef declaration
Type alias declaration (C++11)
Casts
Implicit conversions - Explicit conversions
static_cast - dynamic_cast
const_cast - reinterpret_cast
Memory allocation
new expression	delete expression
Classes
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Virtual function override specifier (C++11) final specifier (C++11)	explicit (C++11) static
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Templates
Class template Function template	Template specialization Parameter packs (C++11)
Miscellaneous
Inline assembly	History of C++

 

Expressions

General

value categories (lvalue, rvalue, xvalue)

order of evaluation (sequence points)

constant expressions

unevaluated expressions

primary expressions

lambda-expression(C++11)

Literals

integer literals

floating-point literals

boolean literals

character literals including escape sequences

string literals

null pointer literal(C++11)

user-defined literal(C++11)

Operators

Assignment operators: a=b, a+=b, a-=b, a*=b, a/=b, a%=b, a&=b, a|=b, a^=b, a<<=b, a>>=b

Increment and decrement: ++a, --a, a++, a--

Arithmetic operators: +a, -a, a+b, a-b, a*b, a/b, a%b, ~a, a&b, a|b, a^b, a<<b, a>>b

Logical operators: a||b, a&&b, !a

Comparison operators: a==b, a!=b, a<b, a>b, a<=b, a>=b, a<=>b(C++20)

Member access operators: a[b], *a, &a, a->b, a.b, a->*b, a.*b

Other operators: a(...), a,b, a?b:c

Default comparisons(C++20)

Alternative representations of operators

Precedence and associativity

Fold expression(C++17)

new-expression

delete-expression

throw-expression

alignof

sizeof

sizeof...(C++11)

typeid

noexcept(C++11)

Operator overloading

Conversions

Implicit conversions

const_cast

static_cast

reinterpret_cast

dynamic_cast

Explicit conversions (T)a, T(a)

User-defined conversion

 

Syntax

' c-char '	(1)
u8 ' c-char '	(2)	(since C++17)
u ' c-char '	(3)	(since C++11)
U ' c-char '	(4)	(since C++11)
L ' c-char '	(5)
' c-char-sequence '	(6)

where

• c-char is either

• a character from the source character set minus single-quote ('), backslash (\), or the newline character,
• escape sequence, as defined in escape sequences
• universal character name, as defined in escape sequences

• c-char-sequence is a sequence of two or more c-chars.

1) narrow character literal or ordinary character literal, e.g. 'a' or '\n' or '\13'. Such literal has type char and the value equal to the representation of c-char in the execution character set. If c-char is not representable as a single byte in the execution character set, the literal has type int and implementation-defined value

2) UTF-8 character literal, e.g. u8'a'. Such literal has type char (until C++20)char8_t (since C++20) and the value equal to ISO 10646 code point value of c-char, provided that the code point value is representable with a single UTF-8 code unit. If c-char is not in Basic Latin or C0 Controls Unicode block, the program is ill-formed.

3) UCS-2 character literal, e.g. u'貓', but not u'🍌' (u'\U0001f34c'). Such literal has type char16_t and the value equal to the value of c-char in Unicode, if it is a part of the basic multilingual plane. If c-char is not part of the BMP, the program is ill-formed.

4) UCS-4 character literal, e.g. U'貓' or U'🍌'. Such literal has type char32_t and the value equal to the value of c-char in Unicode.

5) wide character literal, e.g. L'β' or L'貓'. Such literal has type wchar_t and the value equal to the value of c-char in the execution wide character set. If c-char is not representable in the execution character set (e.g. a non-BMP value on Windows where wchar_t is 16-bit), the value of the literal is implementation-defined.

6) Multicharacter literal, e.g. 'AB', has type int and implementation-defined value.

Notes

Multicharacter literals were inherited by C from the B programming language. Although not specified by the C or C++ standard, compilers implement multicharacter literals as specified in B: the values of each char in the literal initialize successive bytes of the resulting integer, in big-endian zero-padded right-adjusted order, e.g. the value of '\1' is 0x00000001 and the value of '\1\2\3\4' is 0x01020304.

In C, character constants such as 'a' or '\n' have type int, rather than char.