ECMA-334: 14.2.1 Operator precedence and associativity

C# Language Specification

14. Expressions 14.2 Operators 14.2.1 Operator precedence and associativity 14.2.2 Operator overloading 14.2.3 Unary operator overload resolution 14.2.4 Binary operator overload resolution 14.2.5 Candidate user-defined operators 14.2.6 Numeric promotions 14.2.7 Lifted operators

© 2006 ECMA International

14.2.1 Operator precedence and associativity

When an expression contains multiple operators, the precedence of the operators controls the order in which the individual operators are evaluated. [Note: For example, the expression x + y * z is evaluated as x + (y * z) because the * operator has higher precedence than the binary + operator. end note] The precedence of an operator is established by the definition of its associated grammar production. [Note: For example, an additive-expression consists of a sequence of multiplicative-expressions separated by + or - operators, thus giving the + and - operators lower precedence than the *, /, and % operators. end note]

[Note: The following table summarizes the operators in order of precedence from highest to lowest:

Subclause	Category	Operators
14.5	Primary	x.y f(x) a[x] x++ x-- new typeof checked unchecked
14.6	Unary	+ - ! ~ ++x --x (T)x
14.7	Multiplicative	* / %
14.7	Additive	+ -
14.8	Shift	<< >>
14.9	Relational and type-testing	< > <= >= is as
14.9	Equality	== !=
14.10	Logical AND	&
14.10	Logical XOR	^
14.10	Logical OR	|
14.11	Conditional AND	&&
14.11	Conditional OR	||
14.12	Null Coalescing	??
14.13	Conditional	?:
14.14	Assignment	= *= /= %= += -= <<= >>= &= ^= |=

end note]

When an operand occurs between two operators with the same precedence, the associativity of the operators controls the order in which the operations are performed:

• Except for the assignment operators and the null coalescing operator, all binary operators are left-associative, meaning that operations are performed from left to right. [Example: x + y + z is evaluated as (x + y) + z. end example]

• The assignment operators, null coalescing operator and the conditional operator (?:) are right-associative, meaning that operations are performed from right to left. [Example: x = y = z is evaluated as x = (y = z). end example]

Precedence and associativity can be controlled using parentheses. [Example: x + y * z first multiplies y by z and then adds the result to x, but (x + y) * z first adds x and y and then multiplies the result by z. end example]