C++ 运算符优先级
http://en.cppreference.com/w/cpp/language/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 | ||
typeid() |
Run-time type information (see typeid) | ||
const_cast |
Type cast (see const_cast) | ||
dynamic_cast |
Type cast (see dynamic_cast) | ||
reinterpret_cast |
Type cast (see reinterpret_cast) | ||
static_cast |
Type cast (see static_cast) | ||
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 |
16 | = |
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 | ||
17 | throw |
Throw operator (exceptions throwing) | |
18 | , |
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 expression std::cout<<a&b is parsed as (std::cout<<a)&b and not std::cout<<(a&b).
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 expressions *p++ and a=b=c are parsed as *(p++) and a=(b=c), and not as (*p)++ or (a=b)=c because of right-to-left associativity.
An operator's precedence is unaffected by overloading.