Operators in c by anupam

Presented by :
Er. Anupam Sharma
Assistant Professor
Applied Science(CSE) ,CGC-TC
Operators in C by Anupam Sharma

Operators
The symbols which are used to perform logical and
mathematical operations in a C program are called C
operators.
These C operators join individual constants and
variables to form expressions.
Consider the expression A + B * 5.
where, +, * are operators, A, B are variables, 5 is
constant and A + B * 5 is an expression.

Types of Operators based on number of
operands
.
Operators
UNAR
Y
BINARY
TERN
A
RY

Unary Operators
• A unary operator is one which operates on one
value or operand. The minus sign (-) plays a
dual role, it is used for subtraction as a binary
operator and for negation as a unary operator.
This operator has a precedence higher than the
rest of the arithmetic operators.
• result = -x * y;
• in the above expression, if x has a value 20 and
y has a value 2, then result will contain a
negative value of 40 which is -40.
10/19/2015

Binary and Ternary Operators
• Binary
operators?
• Ternary
operators?

Types of ‘C’
operators
1. Arithmetic operators
2. Relational operators
3. Logical operators
4. Assignment operators
5. Increment and Decrement operators
6. Conditional operators
7. Bitwise operators
8. Special operators

1. Arithmetic operator
+ Addition
- Subtraction
* Multiplication
/ Division
% Modulous or modulo division

Example Program
#include<stdio.h>
int main()
{
int a, b, add, sub, mul, div, rem;
printf("Enter a, b values : ");
scanf("%d%d",&a,&b); // Reading two values
add=a+b; // Addition Operator
sub=a-b; // Subtraction Operator
mul=a*b; // Multiplication Operator
div=a/b; // Division Operator
rem=a%b; // Remainder (Modulo) Operator
printf("Result of addition is=%dn", add);
printf("Result of subtraction=%dn", sub);
printf("Result of multiplication is=%dn", mul);
printf("Result of division is=%dn", div);
printf("Result of remainder=%dn",rem);
return 0; }

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2. Relational
operator
C supports six Relational Operators
< 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

• Suppose that a and b are integer variables
whose values are 100 and 4, respectively.
Several arithmetic expressions involving these
variables are shown below, together with their
resulting values.
10/19/2015
a=100, b=4

Example Program
#include<stdio.h>
void main()
{
int a, b;
printf(“Enter values for a and b : ");
scanf("%d %d", &a, &b);
printf("n The < value of a is %d", a<b);
printf("n The <= value of a is %d", a<=b);
printf("n The > value of a is %d", a>b);
printf("n The >= value of a is %d", a>=b);
printf("n The == value of a is %d", a==b);
printf("n The != value of a is %d", a!=b);
}

3.Logical operators
• Logical Operators
– &&, || and ! are the three logical operators.
– expr1 && expr2 has a value 1 if expr1 and expr2 both are
nonzero i.e. if both have values 1(true)
– expr1 || expr2 has a value 1 if either expr1 or expr2 or both
are nonzero i.e 1(true).
– !expr1 has a value 1 if expr1 is zero else 0.
– Example
– if ( marks >= 40 && attendance >= 75 ) grade = ‘P’
– If ( marks < 40 || attendance < 75 ) grade = ‘N’

10/19/2015
Relational And Logical Operators

Logical Operators Example Program
#include<stdio.h>
void main()
{
int a, b;
printf(“Enter values for a and b : ");
scanf(“%d %d", &a, &b);
printf("n %d",(a<b)&&(a!=b));
printf("n %d",(a<b)||(b<a));
printf("n %d",!(a==b));
}

True
!True i.e !1 =0

4. Assignment operators
• Assignment operators are used to assign the result of an expression
to a variable.
• C has a set of ‘shorthand’ assignment operator :
variable name =expression;
Exam - a + = 3;
a = a + 3;
Both are same.
Left side must be an object that
can receive a value

Shorthand Assignment operators
Simple assignment
operator
Shorthand operator
a = a+1 a + =1
a = a-1 a - =1
a = a* (m+n) a * = m+n
a = a / (m+n) a / = m+n
a = a %b a %=b

Assignment Operators Example
#include<stdio.h>
void main()
{
int a, b, c;
printf("Enter the values for a and b : ");
scanf("%d %d",&a,&b);
printf("n the values of= is:%d",c=a+b);
printf("n the values of +=is:%d",c+=b);
printf("n the value of-= is:%d",c-=a);
printf("n the value of *=is:%d",c*=a);
printf("n the value of /=is:%d",c/=b);
printf("n the value of %=is:%d",c%=b);
}

5. Increment and decrement operators.
• Increment Operator ++
a=10;
a++ =10 (post increment but in memory its value is 11)
when you will again call value of a, then a=11
• Decrement Operator --
b=5;
b-- =4 in memory but output will be 5; when you will call b
again then value will be 4.
• Similarly increment and decrement operator is used in
subscripted variables as:
a[ i++]=5;
is equivalent to
a[ i]=5;
i=i+1;

INCREMENT & DECREMENT OPERATORS EXAMPLE
#include<stdio.h>
void main()
{
int a,b,c;
printf("Enter the values for a and b :");
scanf("%d %d", &a, &b);
printf("n The value of c is %d", c=++a);
printf("n The value of c is %d", c=a++);
printf("n The value of c is %d", c=--b);
printf("n The value of c is %d", c=b--);
}

6. Conditional operator
• The conditional expression can be used as
shorthand for some if-else statements. It is a
ternary operator.
• This operator consist of two symbols: the question
mark (?) and the colon (:).
for example:
a=11; b=20;
x=(a>b) ? a : b;
Identifier Test Expression
Exp 1: Exp 2

Conditional Operators Example
#include<stdio.h>
void main()
{
int a, b, x;
printf("Enter the values of a add b : ");
scanf("%d %d", &a, &b);
x=(a>b)?a:b;
printf("Biggest Value is :%d",x);
}

7. Bitwise operator
• C supports bitwise operators for manipulation of data at bit level.
• Bitwise operators may not be applied to float or double.
Operator Meaning
& Bitwise AND operator
| Bitwise OR operator
^ Bitwise exclusive OR operator
~ Binary One's Complement
Operator is a unary operator
used to reverse the bits of an
expression
<< Left shift operator
>> Right shift operator
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 0

Simple program that demonstrates bitwise logical
operators.
#include <stdio.h>
main()
{ unsigned int x = 48; /* 48 = 0011 0000 */
unsigned int y = 13; /* 13 = 0000 1101 */
int z = 0; z =x & y; /* 0 = 0000 0000 */
printf("Bitwise AND Operator - x & y = %dn", z );
z = x | y; /* 61 = 0011 1101 */
printf("Bitwise OR Operator - x | y = %dn", z );
z= x^y; /* 61 = 0011 1101 */
printf("Bitwise XOR Operator- x^y= %dn", z);
z = ~x; /*-61 = 1100 0011 */
printf("Bitwise One's Complement Operator - ~x = %dn", z);
z = x << 2; /* 192 = 1100 0000 */
printf("Bitwise Left Shift Operator x << 2= %dn", z );
z= x >> 2; /* 12 = 0000 1100 */
printf ("Bitwise Right Shift Operator x >> 2= %dn", z ); }

Output:
Bitwise AND Operator - x & y = 0
Bitwise OR Operator - x | y = 61
Bitwise XOR Operator- x^y= 61
Bitwise One's Complement Operator - ~x = -49
Bitwise Left Shift Operator x << 2= 192
Bitwise Right Shift Operator x >> 2= 12

8. Special operators
C supports some special operators such as:
• comma operator “,”
int a=5,b=6;
• size of operator “sizeof()”
• Address operator “&”
• pointer operator “*”
• member selection operator “. and -> ”

Precedence of operators
• Precedence establishes the hierarchy of one set of operators
over another when an arithmetic expression has to be
evaluated.
• It refers to the order in which c evaluates operators.
• The evaluation of operators in an arithmetic
expression takes place from left to right for operators having
equal precedence .

Precedence of operators
BODMAS RULE-
Brackets of Division Multiplication AdditionSubtraction
Brackets will have the highest precedence and have to be evaluated
first, then comes of , then comes division, multiplication, addition
and finally subtraction.
C language uses some rules in evaluating the expressions and they
are called as precedence rules or sometimes also referred to as
hierarchy of operations, with some operators with highest
precedence and some with least.
The 2 distinct priority levels of arithmetic operators in c are-
Highest priority : * / %
Lowest priority : + -

Associativity of operators
•
•
•
•
•
•
• Associativity tells how an operator associates with its operands.
for eg:
Associativity means whether an expression like x R y R z
(where R is a operator such as + or <= ) should be evaluated
`left-to-right' i.e. as (x R y) R z or `right-to-left' i.e. as x R (y
R z)
The assignment operator = associates from right toleft.
Hence the expression on the right is evaluated first and its valueis
assigned to the variable on the left.
Associativity also refers to the order in which c evaluates operators in
an expression having same precedence.
Such type of operator can operate either left to right or vice versa.
The operator () function call has highest precedence & the comma
operator has lowest precedence
All unary , conditional & assignment operators associateRIGHT
TO LEFT .
All other remaining operators associate LEFT TORIGHT

Rules for evaluation of expression
1. First parenthesized sub expression from left to right are
evaluated.
2. If parentheses are nested, the evaluation begins with the
innermost sub expression
3. The precedence rule is applied in determining the order of
application of operators in evaluating sub expressions
4. The associatively rule is applied when 2 or more operators
of the same precedence level appear in a sub expression.
5. Arithmetic expressions are evaluated from left to right using
the rules of precedence
6. When parentheses are used, the expressions within parentheses
assume highest priority

Hierarchy of operators
Operator Description Associativity
( ), [ ] Function call, array element
reference
Left to Right
+, -, ++, - -
,!,~,*,&
Unary plus, minus,
increment, decrement,
logical negation, 1’s
complement, pointer
reference, address
Right to Left
*, / , % Multiplication,
division, modulus
Left to Right

Type Casting
• Type casting is a way to convert a variable from
one data type to another data type.
• When variables and constants of different
types are combined in an expression then they
are converted to same data type. The process
of converting one predefined type into another is
called type conversion.
DATATYPE 1 DATATYPE 2

Implicit Type Casting
• When the type conversion is performed
automatically by the compiler without
programmers intervention, such type of
conversion is known as implicit type conversion
or type promotion.
• For example when you add values having
different data types, both values are first
converted to the same type: when a short int
value and an int value are added together, the
short int value is converted to the int type.
int + short int  int

• C does implicit DataType conversion when the need
arises.
• When a floating point value is assigned to an integer
variable,the decimal portion is truncated.
When a value 156.43 is assigned to an integer variable, 15
is stored and the decimal portion is discarded.
If an integer 200 is assigned to a floating point variable,the
value is converted to 200.000000 and stored.
(integer type variable)a= 156.43 156.43
(float type variable) float b = 200  200.000000

Explicit Type Casting
• The type conversion performed by the programmer
by posing the data type of the expression of specific
type is known as explicit type conversion.
• Type casting in c is done in the following
form:(data_type) expression;
where, data_type is any valid c data type, and
expression may be constant, variable or expression.
For example:
x=(int)a+b*d;

Example
#include <stdio.h>
main()
{
int sum = 17, count = 5;
double mean;
mean = (double) sum / count;
printf("Value of mean :
%fn", mean );
}
Output is
Value of mean : 3.400000
It should be noted here
that the cast operator
has precedence over
division,
so the value of sum is
first converted to type
double and finally it
gets divided by count
yielding a double
value.

Rules for Implicit Type Casting
The following rules have to be followed while
converting the expression from one type to
another to avoid the loss of information:
• All integer types to be converted to float.
• All float types to be converted to double.
• All character types to be converted to integer.

Thank you

Operators in c by anupam

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