What is operator associativity in C?

Answer 1

Operator

Description

Associativity

()
[]
.
->
++ -- Parentheses (function call) (see Note 1)
Brackets (array subscript)
Member selection via object name
Member selection via pointer
Postfix increment/decrement (see Note 2)

left-to-right

++ --
+ -
! ~
(type)
*
&
sizeof Prefix increment/decrement
Unary plus/minus
Logical negation/bitwise complement
Cast (change type)
Dereference
Address
Determine size in bytes right-to-left * / % Multiplication/division/modulus left-to-right + - Addition/subtraction left-to-right << >> Bitwise shift left, Bitwise shift right left-to-right < <=
> >= Relational less than/less than or equal to
Relational greater than/greater than or equal to left-to-right == != Relational is equal to/is not equal to left-to-right & Bitwise AND left-to-right ^ Bitwise exclusive OR left-to-right | Bitwise inclusive OR left-to-right && Logical AND left-to-right Logical OR left-to-right ?: Ternary conditional right-to-left =
+= -=
*= /=
%= &=
^= |=
<<= >>= Assignment
Addition/subtraction assignment
Multiplication/division assignment
Modulus/bitwise AND assignment
Bitwise exclusive/inclusive OR assignment
Bitwise shift left/right assignment right-to-left

,

Comma (separate expressions) left-to-right

Answer 2

Operator precedence describes the order in which C reads expressions. For example, the expressiona=4+b*2 contains two operations, an addition and a multiplication. Does the C compiler evaluate 4+bfirst, then multiply the result by 2, or does it evaluate b*2 first, then add 4 to the result? The operator precedence chart contains the answers. Operators higher in the chart have a higher precedence, meaning that the C compiler evaluates them first. Operators on the same line in the chart have the same precedence, and the "Associativity" column on the right gives their evaluation order.

Answer 3

An operator is a pre-defined token that performs an operation. Some operations use the same token, the actual operation being dictated by the context. For instance, the * token can be used to dereference a pointer operand or to multiply two operands. Similarly, the & token can be used to obtain the address of an operand or to perform a bitwise AND upon two operands.

Operator precedence and associativity in C++ is as follows:

Precedence 1 (left-to-right)

:: Scope resolution operator

Precedence 2 (left-to-right)

++, -- Postfix increment/decrement

() function call

[] array subscript

. member-of reference

-> member-of pointer

Precedence 3 (right-to-left)

++, -- Prefix increment/decrement

+, - Unary plus/minus

!, ~ Logical/bitwise NOT

(type) Typecast

* Indirection (dereference)

& Address-of

sizeof Size of type

new, new[] Dynamic allocation

delete, delete[] Dynamic deallocation

Precedence 4 (left-to-right)

.*, ->* Pointer to member

Precedence 5 (left-to-right)

*, /, % Multiplication, division and modulus

Precedence 6 (left-to-right)

+, - Binary addition/subtraction

Precedence 7 (left-to-right)

<<, >> Bitwise shift left/right

Precedence 8 (left-to-right)

<, <=, >, >= Relational operators

Precedence 9 (left-to-right)

==, != Equality/inequality

Precedence 10 (left-to-right)

& Bitwise AND

Precedence 11 (left-to-right)

^ Bitwise XOR

Precedence 12 (left-to-right)

| Bitwise OR

Precedence 13 (left-to-right)

&& Logical AND

Precedence 14 (left-to-right)

Logical OR

Precedence 15 (right-to-left)

?: Ternary conditional

= Assignment

+=, -= Compound assignment/subtraction

*=, /=, %= Compound multiply/divide/modulus

<<=, >>= Compound shift left/right

&=, |=, ^= Compound bitwise AND/OR/XOR

Precedence 16 (right-to-left)

throw Exception

Precedence 17 (left-to-right)

, Comma