C++运算符优先级

C++运算符优先级

http://www.cppreference.com/wiki/operator_precedence 

小结：不能重载运算符 ::    .    .*      ? :   

Precedence	Operator	Description	Example	Overloadable	Associativity
1	::	Scope resolution operator	Class::age = 2;	no	left to right
2	()	Function call	printf(“Hello world\n”);	yes	left to right
	()	Member initalization	c_tor(int x, int y) : _x(x), _y(y * 10) {}	yes
	[]	Array access	array[4] = 2;	yes
	->	Member access from a pointer	ptr->age = 34;	yes
	.	Member access from an object	obj.age = 34;	no
	++	Post-increment	for (int i = 0; i < 10; i++) cout << i;	yes
	--	Post-decrement	for (int i = 10; i > 0; i--) cout << i;	yes
	dynamic_cast	Runtime-checked type conversion	Y& y = dynamic_cast<Y&>(x);	no
	static_cast	Unchecked type conversion	Y& y = static_cast<Y&>(x);	no
	reinterpret_cast	Reinterpreting type conversion	int const* p = reinterpret_cast<int const*>(0x1234);	no
	const_cast	Cast away/Add constness	int* q = const_cast<int*>(p);	no
	typeid	Get type information	std::type_info const& t = typeid(x);	no
3	!	Logical negation	if (!done) ...	yes	right to left
	not	Alternate spelling for !
	~	Bitwise complement	flags = ~flags;	yes
	compl	Alternate spelling for ~
	++	Pre-increment	for (i = 0; i < 10; ++i) cout << i;	yes
	--	Pre-decrement	for (i = 10; i > 0; --i) cout << i;	yes
	-	Unary minus	int i = -1;	yes
	+	Unary plus	int i = +1;	yes
	*	Dereference	int data = *intPtr;	yes
	&	Address of	int *intPtr = &data;	yes
	sizeof	Size (of the type) of the operand in bytes	size_t s = sizeof(int);	no
	new	Dynamic memory allocation	long* pVar = new long;	yes
	new []	Dynamic memory allocation of array	long* array = new long[20];	yes
	delete	Deallocating the memory	delete pVar;	yes
	delete []	Deallocating the memory of array	delete [] array;	yes
	(type)	Cast to a given type	int i = (int)floatNum;	yes
4	->*	Member pointer selector	ptr->*var = 24;	yes	left to right
	.*	Member object selector	obj.*var = 24;	no
5	*	Multiplication	int i = 2 * 4;	yes	left to right
	/	Division	float f = 10.0 / 3.0;	yes
	%	Modulus	int rem = 4 % 3;	yes
6	+	Addition	int i = 2 + 3;	yes	left to right
	-	Subtraction	int i = 5 - 1;	yes
7	<<	Bitwise shift left	int flags = 33 << 1;	yes	left to right
	>>	Bitwise shift right	int flags = 33 >> 1;	yes
8	<	Comparison less-than	if (i < 42) ...	yes	left to right
	<=	Comparison less-than-or-equal-to	if (i <= 42) ...	yes
	>	Comparison greater-than	if (i > 42) ...	yes
	>=	Comparison greater-than-or-equal-to	if (i >= 42) ...	yes
9	==	Comparison equal-to	if (i == 42) ...	yes	left to right
	eq	Alternate spelling for ==
	!=	Comparison not-equal-to	if (i != 42) ...	yes
	not_eq	Alternate spelling for !=
10	&	Bitwise AND	flags = flags & 42;	yes	left to right
	bitand	Alternate spelling for &
11	^	Bitwise exclusive OR (XOR)	flags = flags ^ 42;	yes	left to right
	xor	Alternate spelling for ^
12	|	Bitwise inclusive (normal) OR	flags = flags | 42;	yes	left to right
	bitor	Alternate spelling for |
13	&&	Logical AND	if (conditionA && conditionB) ...	yes	left to right
	and	Alternate spelling for &&
14	||	Logical OR	if (conditionA || conditionB) ...	yes	left to right
	or	Alternate spelling for ||
15	? :	Ternary conditional (if-then-else)	int i = a > b ? a : b;	no	right to left
16	=	Assignment operator	int a = b;	yes	right to left
	+=	Increment and assign	a += 3;	yes
	-=	Decrement and assign	b -= 4;	yes
	*=	Multiply and assign	a *= 5;	yes
	/=	Divide and assign	a /= 2;	yes
	%=	Modulo and assign	a %= 3;	yes
	&=	Bitwise AND and assign	flags &= new_flags;	yes
	and_eq	Alternate spelling for &=
	^=	Bitwise exclusive or (XOR) and assign	flags ^= new_flags;	yes
	xor_eq	Alternate spelling for ^=
	|=	Bitwise normal OR and assign	flags |= new_flags;	yes
	or_eq	Alternate spelling for |=
	<<=	Bitwise shift left and assign	flags <<= 2;	yes
	>>=	Bitwise shift right and assign	flags >>= 2;	yes
17	throw	throw exception	throw EClass(“Message”);	no
18	,	Sequential evaluation operator	for (i = 0, j = 0; i < 10; i++, j++) ...	yes	left to right