【C++】《C++ Primer Plus》笔记（5）——运算符优先级

递增运算符++和递减运算符--

它们都有点缀和后缀表达式两种。两个版本对操作数的影响是一样的，但是相应的时间不一样，执行的速度可能有细微的差别如果有用户定义的前缀和后缀运算符，使用前缀格式要比使用后缀格式效率高一些。

C++中运算符优先级表

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

# re: C++ 运算符优先级列表 @林缘雨梦

我编了个口诀,帮忙记忆 
阔框点箭域先锋 ① () [] . -> :: 
塞外干旱烦政府 ②sizeof ! ~ + - 
家家户户限制米 ++ -- (type型) &(取址) * 
救灾捐米一点米 ③->* .* 
时余曾促物价减 ④% * / ⑤+ - 
左邻右舍来相告 ⑥<< >> 
老大小凳换大凳 ⑦> < <= >= 
把事说明等不等 ⑧== != 
久雨适宜事宜否 ⑨&⑩^⑾| 
十二雨下十三过 ⑿&&⒀|| 

三梦睡醒灯都灭 ⒁:?(三目运算) ⒂= +=...⒃,(逗号) 

PS：哈哈，佩服天朝人民的智慧。