C/C++优先级和结合率

c/c++优先级列表

C优先级列表

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 right

2

!
~
++
--
-
+
*
&
(type)
sizeof

Logical negation
Bitwise complement
Pre-increment
Pre-decrement
Unary minus
Unary plus
Dereference
Address of
Cast to a given type
Return size in bytes

if( !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 left

3

->*
.*

Member pointer selector
Member pointer selector

ptr->*var = 24;
obj.*var = 24;

left to right4

*
/
%

Multiplication
Division
Modulus

int i = 2 * 4;
float f = 10 / 3;
int rem = 4 % 3;

left to right

5

+
-

Addition
Subtraction

int i = 2 + 3;
int i = 5 - 1;

left to right

6

<<
>>

Bitwise shift left
Bitwise shift right

int flags = 33 << 1;
int flags = 33 >> 1;

left to right

7

<
<=
>
>=

Comparison less-than
Comparison less-than-or-equal-to
Comparison greater-than
Comparison geater-than-or-equal-to

if( i < 42 ) ...
if( i <= 42 ) ...
if( i > 42 ) ...
if( i >= 42 ) ...

 

 

left to right

8

==
!=

Comparison equal-to
Comparison not-equal-to

if( i == 42 ) ...
if( i != 42 ) ...

left to right

9

&

Bitwise AND

flags = flags & 42;

left to right

10

^

Bitwise exclusive OR

flags = flags ^ 42;

left to right

11

|

Bitwise inclusive (normal) OR

flags = flags | 42;

left to right

12

&&

Logical AND

if( conditionA && conditionB ) ...

left to right

13

||

Logical OR

if( conditionA || conditionB ) ...

left to right

14

? :

Ternary conditional (if-then-else)

int i = (a > b) ? a : b;

right to left

15

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

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 assign

int 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 left

16

,

Sequential evaluation operator

for( i = 0, j = 0; i < 10; i++, j++ ) ...

left to right

 

C++优先级列表

 

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)
sizeof

Logical negation
Bitwise complement
Pre-increment
Pre-decrement
Unary minus
Unary plus
Dereference
Address of
Cast to a given type
Return size in bytes

if( !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 selector

ptr->*var = 24;
obj.*var = 24;

left to right4

*
/
%

Multiplication
Division
Modulus

int i = 2 * 4;
float f = 10 / 3;
int rem = 4 % 3;

left to right5

+
-

Addition
Subtraction

int i = 2 + 3;
int i = 5 - 1;

left to right6

<<
>>

Bitwise shift left
Bitwise shift right

int 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-to

if( i < 42 ) ...
if( i <= 42 ) ...
if( i > 42 ) ...
if( i >= 42 ) ...

left to right8

==
!=

Comparison equal-to
Comparison not-equal-to

if( 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 ORint i = (a > b) ? a : bleft to right14? :Ternary conditional (if-then-else)if( conditionA || conditionB ) ...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 assign

int 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