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  ++ 

Suffix/postfix increment and decrement  Lefttoright 
()

Function call  
[]

Array subscripting  
.

Structure and union member access  
>

Structure and union member access through pointer  
(type){list}

Compound literal(C99)  
2  ++ 

Prefix increment and decrement^{[note 1]}  Righttoleft 
+ 

Unary plus and minus  
! ~

Logical NOT and bitwise NOT  
(type)

Type cast  
*

Indirection (dereference)  
&

Addressof  
sizeof

Sizeof^{[note 2]}  
_Alignof

Alignment requirement(C11)  
3  * / %

Multiplication, division, and remainder  Lefttoright 
4  + 

Addition and subtraction  
5  << >>

Bitwise left shift and right shift  
6  < <=

For relational operators < and ≤ respectively  
> >=

For relational operators > and ≥ respectively  
7  == !=

For relational = and ≠ respectively  
8  &

Bitwise AND  
9  ^

Bitwise XOR (exclusive or)  
10  

Bitwise OR (inclusive or)  
11  &&

Logical AND  
12  

Logical OR  
13  ?:

Ternary conditional^{[note 3]}  RighttoLeft 
14^{[note 4]}  =

Simple assignment  
+= =

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  
15  ,

Comma  Lefttoright 
 ↑ The operand of prefix
++
and
can't be a type cast. This rule grammatically forbids some expressions that would be semantically invalid anyway. Some compilers ignore this rule and detect the invalidity semantically.  ↑ The operand of
sizeof
can't be a type cast: the expressionsizeof (int) * p
is unambiguously interpreted as(sizeof(int)) * p
, but notsizeof((int)*p)
.  ↑ The expression in the middle of the conditional operator (between
?
and:
) is parsed as if parenthesized: its precedence relative to?:
is ignored.  ↑ Assignment operators' left operands must be unary (level2 noncast) expressions. This rule grammatically forbids some expressions that would be semantically invalid anyway. Many compilers ignore this rule and detect the invalidity semantically. For example, e = a < d ? a++ : a = d is an expression that cannot be parsed because of this rule. However, many compilers ignore this rule and parse it as e = ( ((a < d) ? (a++) : a) = d ), and then give an error because it is semantically invalid.
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 expression *p++ is parsed as *(p++), and not as (*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 righttoleft associativity.
Notes
Precedence and associativity are independent from order of evaluation.
The standard itself doesn't specify precedence levels. They are derived from the grammar.
In C++, the conditional operator has the same precedence as assignment operators, and prefix ++
and 
and assignment operators don't have the restrictions about their operands.
Associativity specification is redundant for unary operators and is only shown for completeness: unary prefix operators always associate righttoleft (sizeof ++*p is sizeof(++(*p))) and unary postfix operators always associate lefttoright (a[1][2]++ is ((a[1])[2])++). Note that the associativity is meaningful for member access operators, even though they are grouped with unary postfix operators: a.b++ is parsed (a.b)++ and not a.(b++).
References
 C11 standard (ISO/IEC 9899:2011):
 A.2.1 Expressions
 C99 standard (ISO/IEC 9899:1999):
 A.2.1 Expressions
 C89/C90 standard (ISO/IEC 9899:1990):
 A.1.2.1 Expressions
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(...) 