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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 | :: | Left-to-right | |
| 2 | ++ -- | Suffix/postfix | |
type() type{} | |||
() | |||
[] | |||
. -> | |||
| 3 | ++ -- | Prefix | Right-to-left |
+ - | Unary | ||
! ~ | and | ||
(type) | |||
* | (dereference) | ||
& | |||
sizeof | |||
new new[] | |||
delete delete[] | |||
| 4 | .* ->* | Left-to-right | |
| 5 | * / % | ||
| 6 | + - | ||
| 7 | << >> | Bitwise | |
| 8 | < <= | For < and ≤ respectively | |
> >= | For > and ≥ respectively | ||
| 9 | == != | For = and ≠ respectively | |
| 10 | & | ||
| 11 | ^ | (exclusive or) | |
| 12 | | | (inclusive or) | |
| 13 | && | ||
| 14 | || | ||
| 15 | ?: | Right-to-left | |
throw | |||
= | (provided by default for C++ classes) | ||
+= -= | by sum and difference | ||
*= /= %= | by product, quotient, and remainder | ||
<<= >>= | by bitwise left shift and right shift | ||
&= ^= |= | by bitwise AND, XOR, and OR | ||
| 16 | , | Left-to-right |
sizeof can't be a C-style type cast: the expression sizeof (int) * p is unambiguously interpreted as(sizeof(int)) * p, but not sizeof((int)*p).? and :) is parsed as if parenthesized: its precedence relative to ?: is ignored.When parsing an expression, an operator which is listed on some row of the table above with a precedence will be bound tighter (as if by parentheses) to its arguments than any operator that is listed on a row further below it with a lower precedence. For example, the expressions << a & b and *p++ are parsed as ( << a) & b and *(p++), and not as << (a & b) or (*p)++.
Operators that have the same precedence are bound to their arguments in the direction of their associativity. 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 of assignment, but a + b - c is parsed (a + b) - c and not a + (b - c) because of left-to-right associativity of addition and subtraction.
Associativity specification is redundant for unary operators and is only shown for completeness: unary prefix operators always associate right-to-left (delete ++*p is delete(++(*p))) and unary postfix operators always associate left-to-right (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++))
Operator precedence is unaffected by .
Precedence and associativity are compile-time concepts and are independent from , which is a runtime concept.
The standard itself doesn't specify precedence levels. They are derived from the grammar.
, , , , , , and are not included since they are never ambiguous.
Some of the operators have (e.g., and for &&, or for ||, not for !, etc.).
Relative precedence of the ternary conditional and assignment operators differs between C and C++: in C, assignment is not allowed on the right-hand side of a ternary conditional operator, so e = a < d ? a++ : a = dcannot be parsed. Many C compilers use a modified grammar where ?: has higher precedence than =, which parses that as e = ( ((a < d) ? (a++) : a) = d ) (which then fails to compile because ?: is never lvalue in C and =requires lvalue on the left). In C++, ?: and = have equal precedence and group right-to-left, so that e = a < d ? a++ : a = d parses as e = ((a < d) ? (a++) : (a = d)).
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