# 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.