Operators in C

Operators are the symbol which operates on value or a variable. For example: + is a operator to perform addition.

C programming language has wide range of operators to perform various operations. For better understanding of operators, these operators can be classified as:

Operators in C programming
Arithmetic Operators
Increment and Decrement Operators
Assignment Operators
Relational Operators
Logical Operators
Conditional Operators
Bitwise Operators
Special Operators

Arithmetic Operators

Operator Meaning of Operator
+ addition or unary plus
subtraction or  unary minus
* multiplication
/ division
% remainder after division( modulo division)

Example of working of arithmetic operators

/* Program to demonstrate the working of arithmetic operators in C.  */
#include <stdio.h>
int main(){
    int a=9,b=4,c;
    printf("Remainder when a divided by b=%d\n",c);
    return 0;
Remainder when a divided by b=1


Here, the operators +, – and * performed normally as you expected. In normal calculation, 9/4 equals to 2.25. But, the output is 2 in this program. It is because, a and b are both integers. So, the output is also integer and the compiler neglects the term after decimal point and shows answer 2 instead of 2.25. And, finally a%bis 1,i.e. ,when a=9 is divided by b=4, remainder is 1.

Suppose a=5.0, b=2.0, c=5 and d=2
In C programming,

Note: % operator can only be used with integers.

Increment and decrement operators

In C, ++ and -- are called increment and decrement operators respectively. Both of these operators are unary operators, i.e, used on single operand. ++ adds 1 to operand and -- subtracts 1 to operand respectively. For example:

Let a=5 and b=10
a++;  //a becomes 6
a--;  //a becomes 5
++a;  //a becomes 6
--a;  //a becomes 5 

When i++ is used as prefix(like: ++var),++var will increment the value of var and then return it but, if ++ is used as postfix(like: var++), operator will return the value of operand first and then only increment it. This can be demonstrated by an example:

#include <stdio.h>
int main(){
    int c=2,d=2;
    printf("%d\n",c++); //this statement displays 2 then, only c incremented by 1 to 3.
    printf("%d",++c);   //this statement increments 1 to c then, only c is displayed. 
    return 0;



Assignment Operators

The most common assignment operator is =. This operator assigns the value in right side to the left side. For example:

var=5  //5 is assigned to var
a=c;   //value of c is assigned to a
5=c;   // Error! 5 is a constant.
Operator Example Same as
= a=b a=b
+= a+=b a=a+b
-= a-=b a=a-b
*= a*=b a=a*b
/= a/=b a=a/b
%= a%=b a=a%b

Relational Operator

Relational operators checks relationship between two operands. If the relation is true, it returns value 1 and if the relation is false, it returns value 0. For example:


Here, > is a relational operator. If a is greater than ba>b returns 1 if not then, it returns 0.

Relational operators are used in decision making and loops in C programming.

Operator Meaning of Operator Example
== Equal to 5==3 returns false (0)
> Greater than 5>3 returns true (1)
< Less than 5<3 returns false (0)
!= Not equal to 5!=3 returns true(1)
>= Greater than or equal to 5>=3 returns true (1)
<= Less than or equal to 5<=3 return false (0)

Logical Operators

Logical operators are used to combine expressions containing relation operators. In C, there are 3 logical operators:

Operator Meaning of Operator Example
&& Logial AND  If c=5 and d=2 then,((c==5) && (d>5)) returns false.
|| Logical OR If c=5 and d=2 then, ((c==5) || (d>5)) returns true.
! Logical NOT If c=5 then, !(c==5) returns false.


For expression, ((c==5) && (d>5)) to be true, both c==5 and d>5 should be true but, (d>5) is false in the given example. So, the expression is false. For expression((c==5) || (d>5)) to be true, either the expression should be true. Since, (c==5) is true. So, the expression is true. Since, expression (c==5) is true, !(c==5) is false.

Conditional Operator

Conditional operator takes three operands and consists of two symbols ? and : . Conditional operators are used for decision making in C. For example:


If c is greater than 0, value of c will be 10 but, if c is less than 0, value of c will be -10.

Bitwise Operators

A bitwise operator works on each bit of data. Bitwise operators are used in bit level programming.

Operators Meaning of operators
& Bitwise AND
| Bitwise OR
^ Bitwise exclusive OR
~ Bitwise complement
<< Shift left
>> Shift right

Bitwise operator is advance topic in programming . .

Other Operators

Comma Operator

Comma operators are used to link related expressions together. For example:

int a,c=5,d;

The sizeof operator

It is a unary operator which is used in finding the size of data type, constant, arrays, structure etc. For example:

#include <stdio.h>
int main(){
    int a;
    float b;
    double c;
    char d;
    printf("Size of int=%d bytes\n",sizeof(a));
    printf("Size of float=%d bytes\n",sizeof(b));
    printf("Size of double=%d bytes\n",sizeof(c));
    printf("Size of char=%d byte\n",sizeof(d));
    return 0;


Size of int=4 bytes
Size of float=4 bytes
Size of double=8 bytes
Size of char=1 byte

Conditional operators (?:)

Conditional operators are used in decision making in C programming, i.e, executes different statements according to test condition whether it is either true or false.

Syntax of conditional operators


If the test condition is true, expression1 is returned and if false expression2 is returned.

Example of conditional operator

#include <stdio.h>
int main(){
   char feb;
   int days;
   printf("Enter l if the year is leap year otherwise enter 0: ");
   /*If test condition (feb=='l') is true, days will be equal to 29. */
   /*If test condition (feb=='l') is false, days will be equal to 28. */ 
   printf("Number of days in February = %d",days);
   return 0;


Enter l if the year is leap year otherwise enter n: l
Number of days in February = 29

Other operators such as &(reference operator), *(dereference operator) and ->(member selection) operator will be discussed in pointer chapter.


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