C++运算符优先级

C++的优先级在编程中有着重要意义，不注意会使程序的逻辑出错。

1.下面是网站：http://en.cppreference.com/w/cpp/language/operator_precedence 的优先级列表：

  PrecedenceOperatorDescriptionAssociativity1::Scope resolutionLeft-to-right2a++   a--Suffix/postfix increment and decrementtype()   type{}Functional casta()Function calla[]Subscript.   ->Member access3++a   --aPrefix increment and decrementRight-to-left+a   -aUnary plus and minus!   ~Logical NOT and bitwise NOT(type)C-style cast*aIndirection (dereference)&aAddress-ofsizeofSize-of^{[note 1]}new   new[]Dynamic memory allocationdelete   delete[]Dynamic memory deallocation4.*   ->*Pointer-to-memberLeft-to-right5a*b   a/b   a%bMultiplication, division, and remainder6a+b   a-bAddition and subtraction7<<   >>Bitwise left shift and right shift8<   <=For relational operators < and ≤ respectively>   >=For relational operators > and ≥ respectively9==   !=For relational operators = and ≠ respectively10a&bBitwise AND11^Bitwise XOR (exclusive or)12|Bitwise OR (inclusive or)13&&Logical AND14||Logical OR15a?b:cTernary conditional^{[note 2]}Right-to-leftthrowthrow operator=Direct assignment (provided by default for C++ classes)+=   -=Compound assignment by sum and difference*=   /=   %=Compound assignment by product, quotient, and remainder<<=   >>=Compound assignment by bitwise left shift and right shift&=   ^=   |=Compound assignment by bitwise AND, XOR, and OR16,CommaLeft-to-right

2.下面是在网上所找的比较好的列表：

PrecedenceOperatorDescriptionExampleAssociativity1()
[]
->
.
::
++
--Grouping operator
Array access
Member access from a pointer
Member access from an object
Scoping operator
Post-increment
Post-decrement(a + b) / 4;
array[4] = 2;
ptr->age = 34;
obj.age = 34;
Class::age = 2;
for( i = 0; i < 10; i++ ) ...
for( i = 10; i > 0; i-- ) ...left to right2!
~
++
--
-
+
*
&
(type)
sizeofLogical negation
Bitwise complement
Pre-increment
Pre-decrement
Unary minus
Unary plus
Dereference
Address of
Cast to a given type
Return size in bytesif( !done ) ...
flags = ~flags;
for( i = 0; i < 10; ++i ) ...
for( i = 10; i > 0; --i ) ...
int i = -1;
int i = +1;
data = *ptr;
address = &obj;
int i = (int) floatNum;
int size = sizeof(floatNum);right to left3->*
.*Member pointer selector
Member pointer selectorptr->*var = 24;
obj.*var = 24;left to right4*
/
%Multiplication
Division
Modulusint i = 2 * 4;
float f = 10 / 3;
int rem = 4 % 3;left to right5+
-Addition
Subtractionint i = 2 + 3;
int i = 5 - 1;left to right6<<
>>Bitwise shift left
Bitwise shift rightint flags = 33 << 1;
int flags = 33 >> 1;left to right7<
<=
>
>=Comparison less-than
Comparison less-than-or-equal-to
Comparison greater-than
Comparison geater-than-or-equal-toif( i < 42 ) ...
if( i <= 42 ) ...
if( i > 42 ) ...
if( i >= 42 ) ...left to right8==
!=Comparison equal-to
Comparison not-equal-toif( i == 42 ) ...
if( i != 42 ) ...left to right9&Bitwise ANDflags = flags & 42;left to right10^Bitwise exclusive ORflags = flags ^ 42;left to right11|Bitwise inclusive (normal) ORflags = flags | 42;left to right12&&Logical ANDif( conditionA && conditionB ) ...left to right13||Logical ORif( conditionA || conditionB ) ...left to right14? :Ternary conditional (if-then-else)int i = (a > b) ? a : b;right to left15=
+=
-=
*=
/=
%=
&=
^=
|=
<<=
>>=Assignment operator
Increment and assign
Decrement and assign
Multiply and assign
Divide and assign
Modulo and assign
Bitwise AND and assign
Bitwise exclusive OR and assign
Bitwise inclusive (normal) OR and assign
Bitwise shift left and assign
Bitwise shift right and assignint a = b;
a += 3;
b -= 4;
a *= 5;
a /= 2;
a %= 3;
flags &= new_flags;
flags ^= new_flags;
flags |= new_flags;
flags <<= 2;
flags >>= 2;right to left16,Sequential evaluation operatorfor( i = 0, j = 0; i < 10; i++, j++ ) ...left to right

两者结合看即可。

本人经验，仅供参考！