Operators

An operator is a symbol that tells the compiler to perform specific mathematical or logical functions. C language is rich in built-in operators and provides the following types of operators −

  • Arithmetic Operators
  • Relational Operators
  • Logical Operators
  • Bitwise Operators
  • Assignment Operators
  • Misc Operators

Arithmetic operators

C supports all the basic arithmetic operators. The following table shows all the basic arithmetic operators.

Operator Description
+ adds two operands
subtract second operands from first
* multiply two operand
/ divide numerator by denominator
% remainder of division
++ Increment operator – increases integer value by one
Decrement operator – decreases integer value by one

Relational operators

The following table shows all relation operators supported by C.

Operator Description
== Check if two operand are equal
!= Check if two operand are not equal.
> Check if operand on the left is greater than operand on the right
< Check operand on the left is smaller than right operand
>= check left operand is greater than or equal to right operand
<= Check if operand on left is smaller than or equal to right operand

Logical operators

C language supports following 3 logical operators. Suppose a = 1 and b = 0,

Operator Description Example
&& Logical AND (a && b) is false
|| Logical OR (a || b) is true
! Logical NOT (!a) is false

Bitwise operators

Bitwise operators perform manipulations of data at bit level. These operators also perform shifting of bits from right to left. Bitwise operators are not applied to float or double(These are datatypes, we will learn about them in the next tutorial).

Operator Description
& Bitwise AND
| Bitwise OR
^ Bitwise exclusive OR
<< left shift
>> right shift

Now lets see truth table for bitwise &| and ^

a b a & b a | b a ^ b
0 0 0 0 0
0 1 0 1 1
1 0 0 1 1
1 1 1 1 0

The bitwise shift operator, shifts the bit value. The left operand specifies the value to be shifted and the right operand specifies the number of positions that the bits in the value have to be shifted. Both operands have the same precedence.

Example :

a = 0001000
b = 2
a << b = 0100000 
a >> b = 0000010

Assignment Operators

Assignment operators supported by C language are as follows.

Operator Description Example
= assigns values from right side operands to left side operand a=b
+= adds right operand to the left operand and assign the result to left a+=b is same as a=a+b
-= subtracts right operand from the left operand and assign the result to left operand a-=b is same as a=a-b
*= mutiply left operand with the right operand and assign the result to left operand a*=b is same as a=a*b
/= divides left operand with the right operand and assign the result to left operand a/=b is same as a=a/b
%= calculate modulus using two operands and assign the result to left operand a%=b is same as a=a%b

Conditional operator

The conditional operators in C language are known by two more names

  1. Ternary Operator
  2. ? : Operator

It is actually the if condition that we use in C language decision making, but using conditional operator, we turn the if condition statement into a short and simple operator.

The syntax of a conditional operator is :

expression 1 ? expression 2: expression 3

 

Explanation:

  • The question mark “?” in the syntax represents the if part.
  • The first expression (expression 1) generally returns either true or false, based on which it is decided whether (expression 2) will be executed or (expression 3)
  • If (expression 1) returns true then the expression on the left side of ” : “ i.e (expression 2) is executed.
  • If (expression 1) returns false then the expression on the right side of ” : “ i.e (expression 3) is executed.

Special operator

Operator Description Example
sizeof Returns the size of an variable sizeof(x) return size of the variable x
& Returns the address of an variable &x ; return address of the variable x
* Pointer to a variable *x ; will be pointer to a variable x

C Shorthand

C has a special shorthand that simplifies coding of certain type of assignment.

For Example

a = a + 2;

can be written as :

a += 2;

Shorthand works for a binary operators in C.

Syntax :

variable operator = variable / constant / expression

Operators are listed below :

Operators Example Meaning
+= a+=2 a=a+2
-= a-=2 a=a-2
*= a*=2 a=a*2
/= a/=2 a=a/2
%= a%=2 a=a%2
&&= a&&=2 a=a&&2
||= a||=2 a=a||2

Operator Precedence

Operator Associativity
() [] . -> expr++ expr– left-to-right
* & + – ! ~ ++expr –expr (typecast) sizeof right-to-left
* / % 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<

Order of Operation : PEMDAS

  • Parenthesis
  • Exponents
  • Multiplication
  • Division
  • Addition
  • Subtraction