C++运算符优先级

http://en./w/cpp/language/operator_precedence

C++ Operator Precedence

The following table lists the precedence and associativity of C++ operators. Operators are listed top to bottom, in descending precedence.

Precedence	Operator	Description	Associativity
1	::	Scope resolution	Left-to-right
2	++   --	Suffix/postfix increment and decrement
	()	Function call
	[]	Array subscripting
	.	Element selection by reference
	?>	Element selection through pointer
3	++   --	Prefix increment and decrement	Right-to-left
	+	Unary plus and minus
	!   ~	Logical NOT and bitwise NOT
	(type)	Type cast
	*	Indirection (dereference)
	&	Address-of
	sizeof	Size-of
	new, new[]	Dynamic memory allocation
	delete,delete[]	Dynamic memory deallocation
4	.*   ->*	Pointer to member	Left-to-right
5	*   /   %	Multiplication, division, and remainder
6	+	Addition and subtraction
7	<<   >>	Bitwise left shift and right shift
8	<   <=	For relational operators < and ≤ respectively
	>   >=	For relational operators > and ≥ respectively
9	==   !=	For relational = and ≠ respectively
10	&	Bitwise AND
11	^	Bitwise XOR (exclusive or)
12	|	Bitwise OR (inclusive or)
13	&&	Logical AND
14	||	Logical OR
15	:	Ternary conditional	Right-to-left
	=	Direct assignment (provided by default for C++ classes)
	+=   =	Assignment by sum and difference
	*=   /=   %=	Assignment by product, quotient, and remainder
	<<=   >>=	Assignment by bitwise left shift and right shift
	&=   ^=   |=	Assignment by bitwise AND, XOR, and OR
16	throw	Throw operator (for exceptions)
17	,	Comma	Left-to-right

When parsing an expression, an operator which is listed on some row will be bound tighter (as if by parentheses) to its arguments than any operator that is listed on a row further below it. For example, the expressions std::cout<<a&b and *p++ are parsed as (std::cout<<a)&b and*(p++), and not as std::cout<<(a&b) or (*p)++.

Operators that are in the same cell (there may be several rows of operators listed in a cell) are evaluated with the same precedence, in the given direction. For example, the expression a=b=c is parsed as a=(b=c), and not as (a=b)=c because of right-to-left associativity.

An operator's precedence is unaffected by overloading.

Notes

The standard itself doesn't specify precedence levels. They are derived from the grammar.

const_cast, static_cast, dynamic_cast, reinterpret_cast and typeid are not included since they are never ambiguous.

Some of the operators have alternate spellings (e.g., and for &&, or for ||, not for !, etc.).

See also

Order of evaluation of operator arguments at run time.

Common operators
assignment	increment decrement	arithmetic	logical	comparison	member access	other
a = b a = rvalue 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->b a.b a->*b a.*b	a(...) a, b (type) a  :
Special operators
static_cast converts one type to another compatible type  dynamic_cast converts virtual base class to derived class const_cast converts type to compatible type with different cv qualifiers reinterpret_cast converts type to incompatible type new allocates memory delete deallocates memory sizeof queries the size of a type sizeof... queries the size of a parameter 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)