The document discusses various C operators including arithmetic, relational, logical, bitwise, assignment and increment/decrement operators. It provides examples and explanations of how each operator works. Key operator categories covered include arithmetic operators for mathematical operations, relational operators for comparisons, logical operators for logical expressions, bitwise operators for bit-level operations, and assignment operators for assigning values. Precedence rules and associativity of operators are also explained.

1. C Operators
Dr.T.Abirami
Associate Professor
Department of Information Technology
Kongu Engineering College

2. C Operators
• An operator is simply a symbol that is used to perform operations.
types of operators to perform different types of operations in C language.
• Arithmetic Operators
• Relational Operators
• Shift Operators
• Logical Operators
• Bitwise Operators
• Ternary or Conditional Operators
• Assignment Operator
• Other Operators

3. Precedence of Operators in C
• The precedence of operator species that which operator will be
evaluated first and next.
• The associativity specifies the operator direction to be evaluated;
- it may be left to right or right to left.
Example:
int value=10+20*10;
• The value variable will contain 210 because * (multiplicative
operator) is evaluated before + (additive operator).

4. Category Operator Associativity
Postfix () [] -> . ++ - - Left to right
Unary + - ! ~ ++ - - (type)* & sizeof Right to left
Multiplicative * / % Left to right
Additive + - Left to right
Shift << >> Left to right
Relational < <= > >= Left to right
Equality == != Left to right
Bitwise AND & Left to right
Bitwise XOR ^ Left to right
Bitwise OR | Left to right
Logical AND && Left to right
Logical OR || Left to right
Conditional ?: Right to left
Assignment = += -= *= /= %=>>= <<= &= ^= |= Right to left
Comma , Left to right

5. C Arithmetic Operators
• An arithmetic operator performs mathematical operations such as
addition, subtraction, multiplication, division etc., on numerical
values (constants and variables).
Operator Meaning of Operator
+ addition or unary plus
- subtraction or unary minus
* multiplication
/ division
%
remainder after division
(modulo division)

6. // Working of arithmetic operators
#include <stdio.h>
int main()
{
int a = 9,b = 4, c;
c = a+b;
printf("a+b = %d n",c);
c = a-b;
printf("a-b = %d n",c);
c = a*b;
printf("a*b = %d n",c);
c = a/b;
printf("a/b = %d n",c);
c = a%b;
printf("Remainder when a divided by b = %d n",c);
return 0;
}
Output
a+b = 13
a-b = 5
a*b = 36
a/b = 2
Remainder when a divided by b=1

7. C Increment and Decrement Operators
• two operators increment ++ and decrement -- to change the value of an
operand (constant or variable) by 1.
• Increment ++ increases the value by 1
• whereas decrement -- decreases the value by 1.
• These two operators are unary operators, meaning they only operate on a
single operand.

8. ++ and -- operator as prefix and postfix
• ++ operator as a prefix like: ++var, the value of var is incremented by
1; then it returns the value.
• ++ operator as a postfix like: var++, the original value of var is
returned first; then var is incremented by 1.
• The -- operator works in a similar way to the ++ operator except --
decreases the value by 1.
a = 5
++a; // a becomes 6
a++; // a becomes 7
--a; // a becomes 6
a--; // a becomes 5

9. #include <stdio.h>
int main() {
int var1 = 5, var2 = 5;
// 5 is displayed
// Then, var1 is increased to 6.
printf("%dn", var1++);
// var2 is increased to 6
// Then, it is displayed.
printf("%dn", ++var2);
return 0;
}

10. // Working of increment and decrement operators
#include <stdio.h>
int main()
{
int a = 10, b = 100;
float c = 10.5, d = 100.5;
printf("++a = %d n", ++a);
printf("--b = %d n", --b);
printf("++c = %f n", ++c);
printf("--d = %f n", --d);
return 0;
}
Output
++a = 11
--b = 99
++c = 11.500000
--d = 99.500000

11. C Assignment Operators
• An assignment operator is used for assigning a value to a variable.
• The most common assignment operator is =
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

12. // Working of assignment operators
#include <stdio.h>
int main()
{ int a = 5, c;
c = a; // c is 5
printf("c = %dn", c);
c += a; // c is 10
printf("c = %dn", c);
c -= a; // c is 5
printf("c = %dn", c);
c *= a; // c is 25
printf("c = %dn", c);
c /= a; // c is 5
printf("c = %dn", c);
c %= a; // c = 0
printf("c = %dn", c);
return 0;
}
Output
c = 5
c = 10
c = 5
c = 25
c = 5
c = 0

13. C Relational Operators
• A relational operator checks the relationship between two operands.
If the relation is true, it returns 1; if the relation is false, it returns
value 0.
• Relational operators are used in decision making and loops.
Operator Meaning of Operator Example
== Equal to 5 == 3 is evaluated to 0
> Greater than 5 > 3 is evaluated to 1
< Less than 5 < 3 is evaluated to 0
!= Not equal to 5 != 3 is evaluated to 1
>= Greater than or equal to 5 >= 3 is evaluated to 1
<= Less than or equal to 5 <= 3 is evaluated to 0

14. // Working of relational operators
#include <stdio.h>
int main()
{
int a = 5, b = 5, c = 10;
printf("%d == %d is %d n", a, b, a == b);
printf("%d == %d is %d n", a, c, a == c);
printf("%d > %d is %d n", a, b, a > b);
printf("%d > %d is %d n", a, c, a > c);
printf("%d < %d is %d n", a, b, a < b);
printf("%d < %d is %d n", a, c, a < c);
printf("%d != %d is %d n", a, b, a != b);
printf("%d != %d is %d n", a, c, a != c);
printf("%d >= %d is %d n", a, b, a >= b);
printf("%d >= %d is %d n", a, c, a >= c);
printf("%d <= %d is %d n", a, b, a <= b);
printf("%d <= %d is %d n", a, c, a <= c);
return 0;
}
Output
5 == 5 is 1
5 == 10 is 0
5 > 5 is 0
5 > 10 is 0
5 < 5 is 0
5 < 10 is 1
5 != 5 is 0
5 != 10 is 1
5 >= 5 is 1
5 >= 10 is 0
5 <= 5 is 1
5 <= 10 is 1

15. C Logical Operators
• An expression containing logical operator returns either 0 or 1
depending upon whether expression results true or false.
• Logical operators are commonly used in decision making in C
programming.
Operator Meaning Example
&&
Logical AND. True only if
all operands are true
If c = 5 and d = 2 then,
expression ((c==5) &&
(d>5)) equals to 0.
||
Logical OR. True only if
either one operand is
true
If c = 5 and d = 2 then,
expression ((c==5) ||
(d>5)) equals to 1.
!
Logical NOT. True only if
the operand is 0
If c = 5 then, expression
!(c==5) equals to 0.

16. // Working of logical operators
#include <stdio.h>
int main()
{
int a = 5, b = 5, c = 10, result;
result = (a == b) && (c > b);
printf("(a == b) && (c > b) is %d n", result);
result = (a == b) && (c < b);
printf("(a == b) && (c < b) is %d n", result);
result = (a == b) || (c < b);
printf("(a == b) || (c < b) is %d n", result);
result = (a != b) || (c < b);
printf("(a != b) || (c < b) is %d n", result);
result = !(a != b);
printf("!(a != b) is %d n", result);
result = !(a == b);
printf("!(a == b) is %d n", result);
return 0;
}
Output
(a == b) && (c > b) is 1
(a == b) && (c < b) is 0
(a == b) || (c < b) is 1
(a != b) || (c < b) is 0
!(a != b) is 1
!(a == b) is 0

17. Explanation of logical operator program
(a == b) && (c > 5) evaluates to 1 because both operands (a == b) and (c > b) is 1 (true).
(a == b) && (c < b) evaluates to 0 because operand (c < b) is 0 (false).
(a == b) || (c < b) evaluates to 1 because (a = b) is 1 (true).
(a != b) || (c < b) evaluates to 0 because both operand (a != b) and (c < b) are 0 (false).
!(a != b) evaluates to 1 because operand (a != b) is 0 (false). Hence, !(a != b) is 1 (true).
!(a == b) evaluates to 0 because (a == b) is 1 (true). Hence, !(a == b) is 0 (false).

18. C Bitwise Operators
• During computation, mathematical operations like: addition,
subtraction, multiplication, division, etc are converted to bit-level
which makes processing faster and saves power.
• Bitwise operators are used in C programming to perform bit-level
operations.

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

20. truth table of the bitwise operators.
X Y X&Y X|Y X^Y
0 0 0 0 0
0 1 0 1 1
1 0 0 1 1
1 1 1 1 1

21. Bitwise AND operator
• It is denoted by the single ampersand sign (&).
• Two integer operands are written on both sides of the (&) operator. If the
corresponding bits of both the operands are 1, then the output of the bitwise AND
operation is 1; otherwise, the output would be 0.
For example,
We have two variables a and b.
a =6;
b=4;
The binary representation of the above two variables are given below:
a = 0110
b = 0100
When we apply the bitwise AND operation in the above two variables, i.e., a&
b, the output would be:
Result = 0100

22. #include <stdio.h>
int main()
{
int a=6, b=14; // variable declarations
printf("The output of the Bitwise AND operator a&b is %d",a&b);
return 0;
}
In the above code, we have created two variables, i.e., 'a' and 'b'. The values of 'a' and 'b' are 6 and 14 respectively. The
binary value of 'a' and 'b' are 0110 and 1110, respectively. When we apply the AND operator between these two variables,
a AND b = 0110 && 1110 = 0110

24. Bitwise OR operator
• The bitwise OR operator is represented by a single vertical sign (|).
• Two integer operands are written on both sides of the (|) symbol.
• If the bit value of any of the operand is 1, then the output would be 1,
otherwise 0.
We consider two variables,
a = 23;
b = 10;
The binary representation of the above two variables would be:
a = 0001 0111
b = 0000 1010
When we apply the bitwise OR operator in the above two variables, i.e., a|b , then the output would be:
Result = 0001 1111 As we can observe from the above result that the bits of both the operands are
compared one by one; if the value of either bit is 1, then the output would be 1
otherwise 0.

25. #include <stdio.h>
int main()
{
int a=23,b=10; // variable declarations
printf("The output of the Bitwise OR operator a|b is %d",a|b);
return 0;
}

26. Bitwise exclusive OR operator
• Bitwise exclusive OR operator is denoted by (^) symbol. Two operands are written on both sides of
the exclusive OR operator.
• If the corresponding bit of any of the operand is 1 then the output would be 1, otherwise 0.
For example,
We consider two variables a and b,
a = 12;
b = 10;
The binary representation of the above two variables would be:
a = 0000 1100
b = 0000 1010
When we apply the bitwise exclusive OR operator in the above two variables (a^b), then the
result would be:
Result = 0000 1110

27. Bitwise exclusive OR operator
• This operator is a binary operator, denoted by ‘^’. It returns bit by bit XOR of
input values, i.e, if corresponding bits are different, it gives 1, else it gives 0.
For example,
a = 5 = 0101 (In Binary)
b = 7 = 0111 (In Binary)
Bitwise XOR Operation of 5 and 7
0101
^0111
________
0010 = 2 (In decimal)

28. #include <stdio.h>
int main()
{
int a=12,b=10; // variable declarations
printf("The output of the Bitwise exclusive OR operator a^b is %d",a^b);
return 0;
}

29. Bitwise complement operator
• The bitwise complement operator is also known as one's complement
operator.
• It is represented by the symbol tilde (~).
• It takes only one operand or variable and performs complement
operation on an operand.
• When we apply the complement operation on any bits, then 0
becomes 1 and 1 becomes 0.

30. Bitwise complement operator
For example,
If we have a variable named 'a',
a = 8;
The binary representation of the above variable is given below:
a = 1000
When we apply the bitwise complement operator to the operand, then
the output would be:
Result = 0111

31. • This operator is a unary operator, denoted by ‘~’. It returns the one’s complement
representation of the input value, i.e, with all bits inverted, which means it makes
every 0 to 1, and every 1 to 0.
For example,
a = 5 = 0101 (In Binary)
• Bitwise Complement Operation of 5
~ 0101
____1___
0110 = 6 (In decimal)
• Note – Compiler will give 2’s complement of that number, i.e., 2’s complement of
10 will be -6.
• 2’s complement of a binary number is 1 added to the 1’s complement of
the binary number.
Examples:
Bitwise complement operator
~x = -x - 1
~ operators works like
negative integers called with
twos-complement

32. #include <stdio.h>
int main()
{
int a=8; // variable declarations
printf("The output of the Bitwise complement operator ~a is %d",~a);
return 0;
}

33. Bitwise shift operators
• Two types of bitwise shift operators exist in C programming.
• The bitwise shift operators will shift the bits either on the left-side or
right-side.
bitwise shift operator is divided into two categories:
• Left-shift operator
• Right-shift operator

34. Left-shift operator
• It is an operator that shifts the number of bits to the left-side.
Syntax of the left-shift operator
Operand << n (Ex: a<<2)
Where,
• Operand is an integer expression on which we apply the left-shift operation.
• n is the number of bits to be shifted.
• In the case of Left-shift operator, 'n' bits will be shifted on the left-side. The 'n'
bits on the left side will be popped out, and 'n' bits on the right-side are filled
with 0.
• Operand * 2n

35. • Let’s take a number 14.
• Binary representation of 14 is 00001110 (write it using 8 bit)
• 14 = (00001110) 2
• Then 14 << 1 will shift the binary sequence 1 position to the left side.
• Like,
If we shift 14 by 1 position
to the left, output will be
14 * 2 = 28.
If we shift 14 by 2 position
to the left, output will be
14 * 4 = 56.
14 << 1
= 14 * (21)
= 14 * 2
= 28.

36. For example,
Suppose we have a statement:
int a = 5;
The binary representation of 'a' is given below:
a = 0101
If we want to left-shift the above representation by 2, then the statement
would be:
a << 2;
0101<<2 = 00010100

37. #include <stdio.h>
int main()
{
int a=5; // variable initialization
printf("The value of a<<2 is : %d ", a<<2);
return 0;
}

38. Right-shift operator
• Bitwise Right shift operator >> is used to shift the binary sequence to right
side by specified position.
Example
• Let’s take a number 14.
• Binary representation of 14 is 00001110 (using 8 bit)
14 = (00001110) 2
• Then 14 >> 1 will shift the binary sequence by 1 position to the right side.
= 14 >> 1
= 14/ (21)
= 7

40. #include<stdio.h>
int main()
{
int var = 128;
printf("var/2 =%d n",var>>1); //1 position to right
printf("var/4 =%d n",var>>2); //2 position to right
printf("var/8 =%d n",var>>3); //3 position to right
printf("var/16 =%d n",var>>4); //4 position to right
printf("var/32 =%d n",var>>5); //5 position to right
return 0;
}
var/2 =64
var/4 =32
var/8 =16
var/16 =8
var/32 =4

41. #include <stdio.h>
int main()
{
int a=7; // variable initialization
printf("The value of a>>2 is : %d ", a>>2);
return 0;
}

42. Conditional Operator
• The conditional operator is also known as a ternary operator.
• The conditional statements are the decision-making statements which
depends upon the output of the expression.
• It is represented by two symbols, i.e., '?' and ':'.
• As conditional operator works on three operands, so it is also known
as the ternary operator.
Syntax of a conditional operator
(Condition? true_value: false_value);
Example : (A > 100 ? 0 : 1);

43. example
age=19;
(age>=18)? (printf("eligible for voting")) : (printf("not eligible for voting"));

44. #include <stdio.h>
int main()
{
int x=10,y=2;
printf( x > y ? "x is greatern" : "y is greater");
return 0;
}
x is greater

45. #include <stdio.h>
int main()
{
int x=1, y ;
y = ( x ==1 ? 2 : 0 ) ;
printf("x value is %dn", x);
printf("y value is %d", y);
}
OUTPUT:
x value is 1
y value is 2

46. Other Operators
Comma Operator
• Comma operators are used to link related expressions together.
For example:
• int a, c = 5, d;

47. The sizeof operator
The sizeof is a unary operator that returns the size of data (constants, variables, array, structure,
etc).
Example
#include <stdio.h>
int main()
{
int a;
float b;
double c;
char d;
printf("Size of int=%lu bytesn",sizeof(a));
printf("Size of float=%lu bytesn",sizeof(b));
printf("Size of double=%lu bytesn",sizeof(c));
printf("Size of char=%lu byten",sizeof(d));
return 0;
}
Other Operators
Output
Size of int = 4 bytes
Size of float = 4 bytes
Size of double = 8 bytes
Size of char = 1 byte

48. Other operators
•reference operator &,
•dereference operator * and
•member selection operator ->