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An expression is a sequence of operators and their operands, that specifies a computation.

Expression evaluation may produce a result (e.g., evaluation of 2 + 2 produces the result 4) and may generate side-effects (e.g. evaluation of std::printf("%d", 4) prints the character '4' on the standard output).

Each C++ expression is characterized by two independent properties: A type and a value category.

Contents

[edit] General

  • value categories (lvalue, rvalue, glvalue, prvalue, xvalue(since C++11)) classify expressions by their values
  • order of evaluation of arguments and subexpressions specify the order in which intermediate results are obtained

[edit] Operators

Common operators
assignment increment
decrement 		arithmetic logical comparison member
access 		other

a = b
a += b
a -= b
a *= b
a /= b
a %= b
a &= b
a |= b
a ^= b
a <<= b
a >>= b

++a
--a
a++
a--

+a
-a
a + b
a - b
a * b
a / b
a % b
~a
a & b
a | b
a ^ b
a << b
a >> b

!a
a && b
a || b

a == b
a != b
a < b
a > b
a <= b
a >= b
a <=> b

a[...]
*a
&a
a->b
a.b
a->*b
a.*b

function call

a(...)
comma

a, b
conditional

a ? b : c
Special operators

static_cast converts one type to another related type
dynamic_cast converts within inheritance hierarchies
const_cast adds or removes cv-qualifiers
reinterpret_cast converts type to unrelated type
C-style cast converts one type to another by a mix of static_cast, const_cast, and reinterpret_cast
new creates objects with dynamic storage duration
delete destructs objects previously created by the new expression and releases obtained memory area
sizeof queries the size of a type
sizeof... queries the size of a pack (since C++11)
typeid queries the type information of a type
noexcept checks if an expression can throw an exception (since C++11)
alignof queries alignment requirements of a type (since C++11)

[edit] Conversions

[edit] Memory allocation

[edit] Other

[edit] Primary expressions

The operands of any operator may be other expressions or primary expressions (e.g. in 1 + 2 * 3, the operands of operator+ are the subexpression 2 * 3 and the primary expression 1).

Primary expressions are any of the following: