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C - Operators



Operators are used to perform operation on a single operand or two operands. Operators in C can be categorized as follows:

  • Arithmetic operators
  • Assignment operators
  • Comparison operators
  • Increment/Decrement operators
  • Logical operators
  • Bitwise operators
  • Miscellaneous operators

C Arithmetic operators

Arithmetic operators are used to perform arithmetic operations on two operands.

OperatorNameDescription
+AdditionAdd two values
-SubtractionSubtract one value from another
*MultiplicationMultiply two values
/DivisionDivide one value by another
%ModuloReturns remainder of division operation

Example

C Assignment operators

Assignment operators are used to assign values of right hand side expression to left hand side operand.

Operator Expression Equivalent toExample
=a = 5a = 5Example
+=a += ba = a + b
-=a -= ba = a - b
*=a *= ba = a * b
/=a /= ba = a / b
%=a %= ba = a % b
&=a &= ba = a & bMore Info
|=a |= ba = a | bMore Info
^=a ^= ba = a ^ bMore Info
>>=a >>= ba = a >> bMore Info
<<=a <<= ba = a << bMore Info

C Comparison operators

Comparison operators are used to compare values of two operands. It returns true when values matches and returns false when values does not match.

Operator Description
==Equal
!= Not equal
>Greater than
<Less than
>=Greater than or equal to
<=Less than or equal to

Example

C Increment/Decrement operators

Increment and decrement operators are used to increase and decrease the value of variable.

OperatorNameDescriptionExample
++xPre-incrementIncreases the value of x by 1, then returns x.Example
x++Post-incrementReturns x, then increases the value of x by 1.
--xPre-decrementDecreases the value of x by 1, then returns x.Example
x--Post-decrementReturns x, then decreases the value of x by 1.

C Logical operators

Logical operators are used to combine two or more conditions.

Operator Name Description
&&ANDReturns true when all conditions are true
||ORReturns true when any of the conditions is true
!NOTReturns opposite boolean result

More Info

C Bitwise operators

Bitwise operators are used to perform bitwise operations on two operands.

OperatorNameDescriptionMore Info
& ANDReturns 1 if both bits at the same position in both operands are 1, else returns 0More Info
|ORReturns 1 if one of two bits at the same position in both operands is 1, else returns 0More Info
^XORReturns 1 if only one of two bits at the same position in both operands is 1, else returns 0More Info
~ NOTReverse all the bitsMore Info
>>Right shiftThe left operand is moved right by the number of bits present in the right operandMore Info
<<Left shiftThe left operand value is moved left by the number of bits present in the right operandMore Info

C Miscellaneous operators

The table below describes other operators supported by C:

OperatorDescription
comma operator (,)Evaluates each of its operands (from left to right) and returns the value of the last operand.
sizeof()Returns size of a data type, constants or variable.
ternary operator (?:)Returns one of the two values based on value of boolean expression.
Address-of operator (&)Returns address of a variable.
Dereference operator (*)Pointer to a variable.

C Operators Precedence

Operator precedence (order of operations) is a collection of rules that reflect conventions about which procedures to perform first in order to evaluate a given expression.

For example, multiplication has higher precedence than addition. Thus, the expression 1 + 2 × 3 is interpreted to have the value 1 + (2 × 3) = 7, and not (1 + 2) × 3 = 9. When exponent is used in the expression, it has precedence over both addition and multiplication. Thus 3 + 52 = 28 and 3 × 52 = 75.

The following table lists the precedence and associativity of C operators. Operators are listed top to bottom, in descending precedence. Operators with higher precedence are evaluated before operators with relatively lower precedence. When operators have the same precedence, associativity of the operators determines the order in which the operations are performed.

PrecedenceOperatorDescriptionAssociativity
1a++  a--Postfix increment, Postfix decrementLeft to Right
a()Function call
a[]Array subscripting
.Structure and union member access
->Structure and union member access through pointer
(type){list}Compound literal
2++a  --aPrefix increment, Prefix decrementRight to Left
+a  -aUnary plus, Unary minus
!Logical NOT
~Bitwise NOT
(type)Cast
*aIndirection (dereference)
&aAddress-of
sizeofsizeof operator
_AlignofAlignment requirement
3*  /  %Multiplication, Division, RemainderLeft to Right
4+  -Addition, Subtraction
5<<  >>Bitwise left shift and right shift
6<  <=  >  >=Less than, Less than or equal, Greater than, and Greater than or equal
7==  !=Equality and Inequality
8&Bitwise AND
9^Bitwise XOR
10|Bitwise OR
11&&Logical AND
12||Logical OR
13a?b:cConditional (ternary) operatorRight to Left
14=Direct sssignment
+=  -=  *=  /=  %=Compound assignment by sum, difference, product, quotient and remainder
<<=  >>=Compound assignment by Bitwise left shift and right shift
&=  ^=  |=Compound assignment by Bitwise AND, XOR and OR
15,CommaLeft to Right

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