Operators in C
Operators are the foundation of any programming language. We can define operators as symbols that help us to perform specific mathematical and logical computations on operands. In other words, we can say that an operator operates the operands. For example, ‘+’ is an operator used for addition, as shown below:
c = a + b;
Here, ‘+’ is the operator known as the addition operator and ‘a’ and ‘b’ are operands. The addition operator tells the compiler to add both of the operands ‘a’ and ‘b’.
The functionality of the C programming language is incomplete without the use of operators.
C has many builtin operators and can be classified into 6 types:
 Arithmetic Operators
 Relational Operators
 Logical Operators
 Bitwise Operators
 Assignment Operators
 Other Operators
The above operators have been discussed in detail:
1. Arithmetic Operators:
These operators are used to perform arithmetic/mathematical operations on operands. Examples: (+, , *, /, %,++,–). Arithmetic operators are of two types:
a) Unary Operators:
Operators that operate or work with a single operand are unary operators. For example: Increment(++) and Decrement(–) Operators
int val = 5; ++val; // 6
b) Binary Operators:
Operators that operate or work with two operands are binary operators. For example: Addition(+), Subtraction(), multiplication(*), Division(/) operators
int a = 7; int b = 2; cout<<a+b; // 9
2. Relational Operators:
These are used for the comparison of the values of two operands. For example, checking if one operand is equal to the other operand or not, whether an operand is greater than the other operand or not, etc. Some of the relational operators are (==, >= , <= )(See this article for more reference).
int a = 3; int b = 5; a < b; // operator to check if a is smaller than b
3. Logical Operators:
Logical Operators are used to combine two or more conditions/constraints or to complement the evaluation of the original condition in consideration. The result of the operation of a logical operator is a Boolean value either true or false.
For example, the logical AND represented as the â€˜&&â€™ operator in C returns true when both the conditions under consideration are satisfied. Otherwise, it returns false. Therefore, a && b returns true when both a and b are true (i.e. nonzero)(See this article for more reference).
(4 != 5) && (4 < 5); // true
4. Bitwise Operators:
The Bitwise operators are used to perform bitlevel operations on the operands. The operators are first converted to bitlevel and then the calculation is performed on the operands. Mathematical operations such as addition, subtraction, multiplication, etc. can be performed at the bit level for faster processing. For example, the bitwise AND operator represented as ‘&’ in C takes two numbers as operands and does AND on every bit of two numbers. The result of AND is 1 only if both bits are 1(True).
int a = 5, b = 9; // a = 5(00000101), b = 9(00001001) cout << (a ^ b); // 00001100 cout <<(~a); // 11111010
5. Assignment Operators:
Assignment operators are used to assign value to a variable. The left side operand of the assignment operator is a variable and the right side operand of the assignment operator is a value. The value on the right side must be of the same data type as the variable on the left side otherwise the compiler will raise an error.
Different types of assignment operators are shown below:
a) “=”
This is the simplest assignment operator. This operator is used to assign the value on the right to the variable on the left.
Example:
a = 10; b = 20; ch = 'y';
b) “+=”
This operator is the combination of the ‘+’ and ‘=’ operators. This operator first adds the current value of the variable on left to the value on the right and then assigns the result to the variable on the left.
Example:
(a += b) can be written as (a = a + b) If initially value stored in a is 5. Then (a += 6) = 11.
c) “=”
This operator is a combination of ‘‘ and ‘=’ operators. This operator first subtracts the value on the right from the current value of the variable on left and then assigns the result to the variable on the left.
Example:
(a = b) can be written as (a = a  b) If initially value stored in a is 8. Then (a = 6) = 2.
d) “*=”
This operator is a combination of the ‘*’ and ‘=’ operators. This operator first multiplies the current value of the variable on left to the value on the right and then assigns the result to the variable on the left.
Example:
(a *= b) can be written as (a = a * b) If initially, the value stored in a is 5. Then (a *= 6) = 30.
e) “/=”
This operator is a combination of the ‘/’ and ‘=’ operators. This operator first divides the current value of the variable on left by the value on the right and then assigns the result to the variable on the left.
Example:
(a /= b) can be written as (a = a / b) If initially, the value stored in a is 6. Then (a /= 2) = 3.
6. Other Operators:
Apart from the above operators, there are some other operators available in C used to perform some specific tasks. Some of them are discussed here:
a. sizeof operator
 sizeof is much used in the C programming language.
 It is a compiletime unary operator which can be used to compute the size of its operand.
 The result of sizeof is of the unsigned integral type which is usually denoted by size_t.
 Basically, the sizeof the operator is used to compute the size of the variable. (See this article for reference)
b. Comma Operator
 The comma operator (represented by the token) is a binary operator that evaluates its first operand and discards the result, it then evaluates the second operand and returns this value (and type).
 The comma operator has the lowest precedence of any C operator.
 Comma acts as both operator and separator. (See this article for reference)
c. Conditional Operator
 The conditional operator is of the form Expression1? Expression2: Expression3
 Here, Expression1 is the condition to be evaluated. If the condition(Expression1) is True then we will execute and return the result of Expression2 otherwise if the condition(Expression1) is false then we will execute and return the result of Expression3.
 We may replace the use of if..else statements with conditional operators. (See this article for reference)
d. dot (.) and arrow (>) Operators
 Member operators are used to reference individual members of classes, structures, and unions.
 The dot operator is applied to the actual object. (See this article for reference)
 The arrow operator is used with a pointer to an object. (See this article for reference)
e. Cast Operator
 Casting operators convert one data type to another. For example, int(2.2000) would return 2.
 A cast is a special operator that forces one data type to be converted into another.
 The most general cast supported by most of the C compilers is as follows âˆ’ [ (type) expression ]. (See this article for reference)
f. &,* Operator
 Pointer operator & returns the address of a variable. For example &a; will give the actual address of the variable.
 Pointer operator * is a pointer to a variable. For example *var; will pointer to a variable var. (See this article for reference
Below is the implementation of the abovementioned operators:
C
// C Program to Demonstrate the working concept of // Operators #include <stdio.h> int main() { int a = 10, b = 5; // Arithmetic operators printf ( "Following are the Arithmetic operators in C\n" ); printf ( "The value of a + b is %d\n" , a + b); printf ( "The value of a  b is %d\n" , a  b); printf ( "The value of a * b is %d\n" , a * b); printf ( "The value of a / b is %d\n" , a / b); printf ( "The value of a % b is %d\n" , a % b); printf ( "The value of a++ is %d\n" , a++); // First print (a) and then increment it // by 1 printf ( "The value of a is %d\n" , a); // First print (a+1) and then decrease it // by 1 printf ( "The value of ++a is %d\n" , ++a); // Increment (a) by (a+1) and then print printf ( "The value of a is %d\n" , a); // Decrement (a+1) by (a) and then print // Assignment Operators > used to assign values to // variables int a =3, b=9; char d='d'; // Comparison operators // Output of all these comparison operators will be (1) // if it is true and (0) if it is false printf ( "\nFollowing are the comparison operators in C\n" ); printf ( "The value of a == b is %d\n" , (a == b)); printf ( "The value of a != b is %d\n" , (a != b)); printf ( "The value of a >= b is %d\n" , (a >= b)); printf ( "The value of a <= b is %d\n" , (a <= b)); printf ( "The value of a > b is %d\n" , (a > b)); printf ( "The value of a < b is %d\n" , (a < b)); // Logical operators printf ( "\nFollowing are the logical operators in C\n" ); printf ( "The value of this logical and operator ((a==b) " "&& (a<b)) is:%d\n" , ((a == b) && (a < b))); printf ( "The value of this logical or operator ((a==b) " " (a<b)) is:%d\n" , ((a == b)  (a < b))); printf ( "The value of this logical not operator " "(!(a==b)) is:%d\n" , (!(a == b))); return 0; } 
Following are the Arithmetic operators in C The value of a + b is 15 The value of a  b is 5 The value of a * b is 50 The value of a / b is 2 The value of a % b is 0 The value of a++ is 10 The value of a is 11 The value of ++a is 11 The value of a is 10 Following are the comparison operators in C The value of a == b is 0 The value of a != b is 1 The value of a >= b is 1 The value of a <= b is 0 The value of a > b is 1 The value of a < b is 0 Following are the logical operators in C The value of this logical and operator ((a==b) && (a<b)) is:0 The value of this logical or operator ((a==b)  (a<b)) is:0 The value of this logical not operator (!(a==b)) is:1
Operator Precedence Chart
The below table describes the precedence order and associativity of operators in C. The precedence of the operator decreases from top to bottom.
Precedence 
Operator 
Description 
Associativity 

1 
() 
Parentheses (function call) 
lefttoright 
[] 
Brackets (array subscript) 
lefttoright 

. 
Member selection via object name 
lefttoright 

> 
Member selection via a pointer 
lefttoright 

a++/a– 
Postfix increment/decrement (a is a variable) 
lefttoright 

2 
++a/–a 
Prefix increment/decrement (a is a variable) 
righttoleft 
+/ 
Unary plus/minus 
righttoleft 

!~ 
Logical negation/bitwise complement 
righttoleft 

(type) 
Cast (convert value to temporary value of type) 
righttoleft 

* 
Dereference 
righttoleft 

& 
Address (of operand) 
righttoleft 

sizeof 
Determine size in bytes on this implementation 
righttoleft 

3 
*,/,% 
Multiplication/division/modulus 
lefttoright 
4 
+/ 
Addition/subtraction 
lefttoright 
5 
<< , >> 
Bitwise shift left, Bitwise shift right 
lefttoright 
6 
< , <= 
Relational less than/less than or equal to 
lefttoright 
> , >= 
Relational greater than/greater than or equal to 
lefttoright 

7 
== , != 
Relational is equal to/is not equal to 
lefttoright 
8 
& 
Bitwise AND 
lefttoright 
9 
^ 
Bitwise exclusive OR 
lefttoright 
10 
 
Bitwise inclusive OR 
lefttoright 
11 
&& 
Logical AND 
lefttoright 
12 
 
Logical OR 
lefttoright 
13 
?: 
Ternary conditional 
righttoleft 
14 
= 
Assignment 
righttoleft 
+= , = 
Addition/subtraction assignment 
righttoleft 

*= , /= 
Multiplication/division assignment 
righttoleft 

%= , &= 
Modulus/bitwise AND assignment 
righttoleft 

^= , = 
Bitwise exclusive/inclusive OR assignment 
righttoleft 

<>= 
Bitwise shift left/right assignment 
righttoleft 

15 
, 
expression separator 
lefttoright 
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