# Operators

suggest change## Introduction

An operator in a programming language is a symbol that tells the compiler or interpreter to perform a specific mathematical, relational or logical operation and produce a final result.

C has many powerful operators. Many C operators are binary operators, which means they have two operands. For example, in `a / b`

, `/`

is a binary operator that accepts two operands (`a`

, `b`

). There are some unary operators which take one operand (for example: `~`

, `++`

), and only one ternary operator `? :`

.

## Syntax

- expr1 operator
- operator expr2
- expr1 operator expr2
- expr1 ? expr2 : expr3

## Remarks

Operators have an *arity*, a *precedence* and an *associativity*.

*Arity*indicates the number of operands. In C, three different operator arities exist:- Unary (1 operand)
- Binary (2 operands)
- Ternary (3 operands)
*Precedence*indicates which operators “bind” first to their operands. That is, which operator has priority to operate on its operands. For instance, the C language obeys the convention that multiplication and division have precedence over addition and subtraction:

a * b + c

Gives the same result as

(a * b) + c

If this is not what was wanted, precedence can be forced using parentheses, because they have the *highest* precedence of all operators.

a * (b + c)

This new expression will produce a result that differs from the previous two expressions.

The C language has many precedence levels; A table is given below of all operators, in descending order of precedence.

**Precedence Table**

Operators | Associativity ------ | ------ (), [], ->, . | left to right !, ~, ++, --, +, -, * (dereference), (type), sizeof | right to left * (multiplication), /, %, | left to right +, - | left to right <<, >> | left to right <, <=, >, >= | left to right ==, != | left to right & | left to right ^ | left to right | | left to right && | left to right || | left to right ?: | right to left =, +=, -=, *=, /=, %=, &=, ^=, |=, <<=, >>= | right to left , | left to right

*Associativity*indicates how equal-precedence operators binds by default, and there are two kinds:*Left-to-Right*and*Right-to-Left*. An example of*Left-to-Right*binding is the subtraction operator (`\-`

). The expression

a - b - c - d

has three identical-precedence subtractions, but gives the same result as

((a - b) - c) - d

because the left-most `\-`

binds first to its two operands.

An example of *Right-to-Left* associativity are the dereference `\*`

and post-increment `++`

operators. Both have equal precedence, so if they are used in an expression such as

* ptr ++

, this is equivalent to

* (ptr ++)

because the rightmost, unary operator (`++`

) binds first to its single operand.