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# C++ Operator Precedence

From cppreference.com
< cpp‎ | language

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 | `a++` `a--` | Suffix/postfix increment and decrement
`type()` `type{}` | Functional cast
`a()` | Function call
`a[]` | Subscript
`.` `->` | Member access
3 | `++a` `--a` | Prefix increment and decrement | Right-to-left
`+a` `-a` | Unary plus and minus
`!` `~` | Logical NOT and bitwise NOT
`(type)` | C-style cast
`*a` | Indirection (dereference)
`&a` | Address-of
`sizeof` | Size-of[note 1]
`new` `new[]` | Dynamic memory allocation
`delete` `delete[]` | Dynamic memory deallocation
4 | `.*` `->*` | Pointer-to-member | Left-to-right
5 | `a*b` `a/b` `a%b` | Multiplication, division, and remainder
6 | `a+b` `a-b` | Addition and subtraction
7 | `<<` `>>` | Bitwise left shift and right shift
8 | `<` `<=` | For relational operators < and ≤ respectively
`>` `>=` | For relational operators > and ≥ respectively
9 | `==` `!=` | For relational operators = and ≠ respectively
10 | `a&b` | Bitwise AND
11 | `^` | Bitwise XOR (exclusive or)
12 | `|` | Bitwise OR (inclusive or)
13 | `&&` | Logical AND
14 | `||` | Logical OR
15 | `a?b:c` | Ternary conditional[note 2] | Right-to-left
`throw` | throw operator
`=` | Direct assignment (provided by default for C++ classes)
`+=` `-=` | Compound assignment by sum and difference
`*=` `/=` `%=` | Compound assignment by product, quotient, and remainder
`<<=` `>>=` | Compound assignment by bitwise left shift and right shift
`&=` `^=` `|=` | Compound assignment by bitwise AND, XOR, and OR
16 | `,` | Comma | Left-to-right

1. ↑ The operand of `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)`.
2. ↑ The expression in the middle of the conditional operator (between `?` 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 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 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 operator overloading. For example, std::cout << a ? b : c; parses as (std::cout << a) ? b : c; because the precedence of arithmetic left shift is higher than the conditional operator.

### [edit] Notes

Precedence and associativity are compile-time concepts and are independent from order of evaluation, which is a runtime concept.

The standard itself doesn't specify precedence levels. They are derived from the grammar.

`const_cast`, `static_cast`, `dynamic_cast`, `reinterpret_cast`, `typeid`, `sizeof...`, `noexcept` and `alignof` are not included since they are never ambiguous.

Some of the operators have alternate spellings (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 = d cannot 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)).

### [edit] See also

Common operators
assignment | increment decrement | arithmetic | logical | comparison | member access | other
a = b a += b a -= b a *= b a /= b a %= b a &= b a |= b a ^= b a <<= b a >>= b | ++a --a a++ a-- | +a -a a + b a - b a * b a / b a % b ~a a & b a | b a ^ b a << b a >> b | !a a && b a || b | a == b a != b a < b a > b a <= b a >= b | a[b] *a &a a->b a.b a->*b a.*b | a(...) a, b ? :
Special operators
`static_cast` converts one type to another related type `dynamic_cast` converts within inheritance hierarchies `const_cast` adds or removes cv qualifiers `reinterpret_cast` converts type to unrelated type C-style cast converts one type to another by a mix of `static_cast`, `const_cast`, and `reinterpret_cast` `new` creates objects with dynamic storage duration `delete` destructs objects previously created by the new expression and releases obtained memory area `sizeof` queries the size of a type `sizeof...` queries the size of a parameter pack (since C++11) `typeid` queries the type information of a type `noexcept` checks if an expression can throw an exception (since C++11) `alignof` queries alignment requirements of a type (since C++11)

C documentation for C operator precedence

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