c programming Operators

c programming Operators

Operators are ‘C’ tokens which can join together individual constants, variables array elements, and function references. Operators act upon data items called as operands.


  • Arithmetic operators
  • Relational operators
  • Logical operators
  • Assignment operator
  • Increment and decrement operator
  • Conditional operator
  • Bitwise operator
  • Special operator
Arithmetic Operators
Arithmetic operatorMeaning
+Adding or unary plus
Subtraction or unary minus
% Modulo division
  • For arithmetic operations, operands must be numeric values.
  • Here modulo division produces reminder of integer division.
  • arithmetic operations are classified as
    • Integer arithmetic
    • Real arithmetic
    • Mixed mode arithmetic

Integer arithmetic: Both the operands are an integer in integer arithmetic. It always yields an integer value.
Ex: int a=10,b=5;  a+b;  a-b; a*b; a/b ; a%b etc.

Real arithmetic: Both the operands are real in real arithmetic. It yields real values as a result. It cannot be applied to the % operator.

float a=10.0, b=5.0; 
a+b=10.0+5.0=15.0 i.e. 15.000000 
a-b= 10.0-5.0 =5.0 i.e. 5.000000 
a*b= 10.0*5.0 =50.0 i.e. 50.000000 
a/b= 10.0/5.0 = 2.0 i.e. 2.000000 
a%b=10.0%5.0 (invalid expression)

Mixed Mode Arithmetic: when one operand is an integer and other is real it is known as mixed mode arithmetic. Here the result will always be real.

int a=10; 
float b=5.0; 
a-b = 10-5.0 =5.0 
a*b = 10*5.0 =50.0 
a/b = 10/5.0 = 2.0 
a%b=10%5.0 (invalid expression)
Relational Operators

These are used to compare two quantities. These operators always return 1(true) or 0 (false). If the expression is true then it returns with 1 else 0

Relational Operator Action
<is less than
<=is less than or equal to
>is greater than
>=is greater than or equal to
==is equal to
!=is not equal to


10<50 (false)
10>51 (true)
10==150 (false)
10!=151 (true)
(10+5)==(3*5)1 (true)
Logical Operators
logical Operator     Action
&&logical AND
||logical OR
!logical NOT
  • Logical expression combines two or more relational expressions.
  • Logical operators are used to testing more than one condition and make a decision.
  • Logical AND: The result of logical AND expression will be true only when both the relational expression is true.

Syntax:exp1 && exp2;

  • Logical OR: The result of logical OR expression will be false only when both relational expressions are false.

Syntax: exp1 || exp2;

  • Logical NOT: The result of the expression will be true if the expression is false and vice versa


int a=10,b=15, c=20,i; 
i= (a>b) && (b<c); //The value of i in this expression will be 0. 
i= (a<b) && (b<c); //The value of i in this expression will be 1. 
i= (a>b) || (b<c); //The value of i in this expression will be 1. 
i= ! (a>b); //The value of i in this expression will be 1.
Assignment Operators

The operators are used to assign the result of an expression to a variable
Syntax: Variable = exp;

Assignment Operator  Ex: int a=10,b=5;Action
a=a+1; or a+=1;adds 1 to a and assigns the value to a
a=a-1; or a-=1;decrements a by 1 and assigns the value to a
a=a/(b+1) or a/=b+1;divides a by (b+1) and assigns the result in a
a*=b+2; or a=a*(b+2)multiplies (b+2) with a and assigns the result in a

Increment and Decrement operators

  • These operators are represented as ‘++’ and ‘–’.
  • ++ Increments operand by 1 and –- decrement the value by 1.
  • These are the unary operators and takes the following forms,
Operator (int a,b)ActionResult
a=1;  b=++a;pre-incrementincrements a value by 1 and assigns the value to b. i.e., a=2 and b=2
a= 1;  b=a++;post-incrementAssigns the value to b then increments a value by 1. i.e., a=2 and b=1
a=2;  b=–a;pre-decrementdecrements a value by 1 and assigns the value to b. i.e., a=1 and b=1
a=2;  b=a–;post-decrementAssigns the value to b then decrements a value by 1. i.e., a=1 and b=2
Conditional Operator
  • It is also known as a ternary operator
    Syntax: exp1 ? exp2 : exp3;
    Where exp1, exp2, and exp3 are expressions


int a=5,b=10,c=15,y; 
y=(a>b) ? b : c; //The value of y is 15 
y=(a<b) ? b : c; //The value of y is 10


/* Greatest of three numbers using conditional operation */ 
int a=5,b=10,c=15,y; 
y=(a>b && a>c) ? a: (b>c) ? b: c; //Here greatest of three numbers is stored in x;
Bitwise Operators

Bitwise operators are similar to that of logical operators except that they work on binary bits. When bitwise operators are used with variables, they are internally converted to binary numbers and then bitwise operators are applied on individual bits.

Bitwise operators do manipulation on bit stored in memory. These operators work with char and int type only. They cannot use floating point numbers.

Bitwise OperatorsAction
~1’s compliment
|Bitwise OR
^Bitwise exclusive OR
&Bitwise AND
<<Left shift
 >>Right shift


int a=10,b=8; //Assum that int size is 2 bytes 
/* The equivalent binary value of a is 0000 0000 0000 1010 
   The equivalent binary value of b is 0000 0000 0000 1000 
printf("%d", a & b); // The value of a & b = 0000 0000 0000 1000 i.e.,8 

printf("%d", a|b); // The value of a | b = 0000 0000 0000 1010 i.e., 10 

printf("%d", a^b); //The value of a ^ b= 0000 0000 0000 0010 i.e., 2 

printf("%d" ,a<<2); 
     a(10) binary is 0000 0000 0000 1010 a<<2. 
     It left shift the binary bits twice. i.e.,0000 0000 0010 1000 i.e. 40 */ 

printf("%d", a>>2); 
    a(10) binary is 0000 0000 0000 1010 a>>2. 
    It right shifts the binary bits twice. i.e., 0000 0000 0000 0010 i.e. 2 
Special Operator

There are some special operators available in ‘C’ such as sizeof operator and member selection operators (. and →).

sizeof Operator: It returns numbers of bytes the operand occupies; operand may be a variable, a constant, or a data type qualifier.
Syntax: sizeof(operand)

int y; 
y= sizeof (int); //here value of y will be 2 byte it its 16bit compiler

Member Operators: These are used to access members of structure and unions.

Operators priority wise





Function call

Square bracket

Structure operator

Structure operator

Left to Right1st








Unary plus

Unary minus



Not operator

Ones complement

Pointer operator

Address operator

Size of an object

Type case

Right to Left2nd





Modular division

Left to Right3rd




Left to Right4th


Left shift

Right shift

Left to Right5th




Less than

Less than or equal to

Greater than

Greater than or equal to

Left to Right6th




Left to right7th
&Bitwise ANDLeft to right8th
^Bitwise XORLeft to right9th
|Bitwise ORLeft to right10th
&&Logical ANDLeft to right11th
||Logical ORLeft to right12th
? :Conditional operatorRight to left13th
=, +=,-=,*=, /=, %=, &=,^=, |=, <<=, >>=Assignment operatorsRight to left14th


An expression in C is constructed using operators, variables and or constants.


x<y x<y && x>5


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