1. c语言优先级 详细表格
C Operator Precedence Table
This page lists C operators in order of precedence (highest to lowest). Their associativity indicates in what order operators of equal precedence in an expression are applied.
|
Operator |
Description |
Associativity |
|---|---|---|
| ( ) [ ] . -> ++ -- |
Parentheses (function call) (see Note 1) Brackets (array subscript) Member selection via object name Member selection via pointer Postfix increment/decrement (see Note 2) |
left-to-right |
| ++ -- + - ! ~ (type) * & sizeof |
Prefix increment/decrement Unary plus/minus Logical negation/bitwise complement Cast (convert value to temporary value of type) Dereference Address (of operand) Determine size in bytes on this implementation |
right-to-left |
| * / % | Multiplication/division/modulus | left-to-right |
| + - | Addition/subtraction | left-to-right |
| << >> | Bitwise shift left, Bitwise shift right | left-to-right |
| < <= > >= |
Relational less than/less than or equal to Relational greater than/greater than or equal to |
left-to-right |
| == != | Relational is equal to/is not equal to | left-to-right |
| & | Bitwise AND | left-to-right |
| ^ | Bitwise exclusive OR | left-to-right |
| | | Bitwise inclusive OR | left-to-right |
| && | Logical AND | left-to-right |
| | | | Logical OR | left-to-right |
| ? : | Ternary conditional | right-to-left |
| = += -= *= /= %= &= ^= |= <<= >>= |
Assignment Addition/subtraction assignment Multiplication/division assignment Modulus/bitwise AND assignment Bitwise exclusive/inclusive OR assignment Bitwise shift left/right assignment |
right-to-left |
|
, |
Comma (separate expressions) | left-to-right |
|
||
//z 2013-09-23 18:14:19 IS2120@BG57IV3 T1608511706.K.F1292029078[T4,L61,R1,V20]
/* postinc.c -- 070223 (sjd)
Demo precedence of post-increment
*/
#include <stdio.h>
int main()
{
int i[] = {3, 5};
int *p = i;
int j = --*p++;
printf("j = %d\n\n", j);
system("pause");
return 0;
}
//z 2013-09-23 18:22:39 IS2120@BG57IV3 T4026930875.K.F1292029078[T5,L62,R1,V23]2. c++ 优先级 操作符
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&band *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 |
+a |
!a |
a == b |
a[b] |
a(...) |
| Special operators | ||||||
|
static_cast converts one type
to another compatible type |
||||||
③. 对应 url
http://en.cppreference.com/w/cpp/language/operator_precedence
http://www.difranco.net/compsci/C_Operator_Precedence_Table.htm