本文详细介绍了C++中各种运算符的优先级和结合性，帮助开发者更好地理解和运用这些基本概念。
转载 http://en.cppreference.com/w/cpp/language/operator_precedence
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&b
and *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 | ||||||
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