C
Operators
o
v C Operators
What is operators?
In simple word operators are those which operator anything like as
data,maths,information etc i.e.. When we talking about C operators, i want to
say you that C is very rich in operators.
Operators tells to compiler that what do with data. There are mainly operators
in c as following:
1. Logical Operators
2. Bitwise Operators
3. Relational Operators
4. Assignment Operators
5. Sizeof Operators
6. Increment and Decrement operators
7. Comma operators
8. Type cast operator
9. Conditional operators or ternary
operators
Sometime operators are divided according numbers of operands. So there
are three types of operators as following :
Operators


Unary

Binary

Ternary


operand

single

double

third

works

right to left

left to right

left to right

Example_1

++ , 

+, , *, /

? :

Example_2

! , ~

&& , 

1.Logical Operator
When we use if, for,
while then use one condition at once time what happen if we examine condition
more than one? In this case we use logical operators. So logical operators are
used to combine two or more condition.
There are three types of logical operators as following:
There are three types of logical operators as following:
Operator
symbol

Name

&&

Logical AND



Logical OR

!

Logical NOT

LOGICAL
AND OPERATOR ( && )
The condition is true
if and only if both two expression are true otherwise condition false. The
truth table of logical AND operators end of this chapter.
LOGICAL
OR OPERATOR (  )
The condition is
true if one of expression is true and condition will be false only if both
expression are false. See example of  operator at end of this chapter.
LOGICAL
NOT OPERATOR ( ! )
It reverse the
expression i.e if the expression evaluates to a nonzero value,
then applying ! operator to it results into a 0 and vice versa. The final
result (after applying ! ) 0 or 1 is considered to be false or true
respectively.
Example of above three
operators :
//following
table con = condition.
con
1

Con
2

con
1 && con 2

con
1  con 2

! con
1

! con
2

False

False

False

False

True

True

False

True

False

True

True

False

True

False

False

True

False

True

True

True

True

True

False

False

Some numerical example
:
if(10>5 && 1000<2001)
// True
while(
; num>=1  num<=100
; ) // if num=1 True
Now some discuss
of NOT operator when we write condition if( 1 ! =
0 ) what is mean it? It is mean "one is
not equal to zero", so is condition TRUE or False? It is true.
Let's understand following example :
if(sex!='M')
printf("Person
is Female");
else
printf("Person
is Male");
In above example
evaluate first printf if condition is false otherwise evaluate second printf.
!(x<22)
it is also we write (x>=22) // both are equal.
Write a C
Program by using Logical AND and OR Operator
Statement of C Program: This Program illustrates the logical ANDing and ORing operations:
#include<stdio.h>
#include<conio.h>
void main()
{
int a , b , c;
clrscr();
a = 4 , b = 3;
b = abc;
a = a && bc;
printf("%d" , a\n);
printf("%d" , b\n);
printf("%d" , c\n);
}
Output:
1
1
1
2.Bitwise operators
The smallest element in
memory on which are able to operate is called byte; and the programming
language are byte oriented. One of the c powerful features is a set of bit
manipulation operators. There are various bitwise operators in C as following
table; we learn all step by step :
Operators

Name

&

Bitwise AND



Bitwise OR

^

Bitwise XOR(exclusive OR)

>>

Left shift

<<

right shift

~

One's complement

These operators can operate upon ints and chars but not on floats and doubles. Bits are numbered from zero onwards, increasing from right to left as following figure:
7

6

5

4

3

2

1

0

8 bit Character

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

16 bit Integer

Bitwise
AND Operator (&)
The & operator operates on a pair of bits to yield a resultant bit. The rules that decide the value of the resultant bit also called truth table are shown below:
Bit x

Bit y

x & y

0

0

0

0

1

0

1

0

0

1

1

1

The best use of the AND operator is to check whether a particular bit of an operand is ON or OFF. The meaning of ON means 1 and OFF means 0. The following program puts this logic clear:
/*Example of
bitwise AND operator*/
#include<stdio.h>
#include<conio.h>
void main()
{
int x=45;
int y=37;
int z;
clrscr();
z = x & y;
printf("\nValue
of z=%d",z);
}
Output of above
program:
Value of z=37
In above program compiler first calculate the binary x and y which is 111101 and 100101 respectly. After this its work on bitwise operator and final result is 37 which binary code are 100101. The following table shown the result :
Values

binary code

x = 45

111101

y = 37

100101

z = x & y

100101

Bitwise
OR (  )
Truth table for bitwise
OR are as following :
x

y

z = x  y

0

0

0

0

1

1

1

0

1

1

1

1

Bitwise
XOR ( ^ )
It is also called
exclusive OR. If there are similar bit then its return 0 otherwise its return
1. Let watch truth table of x^y :
x

y

z = x ^ y

0

0

0

0

1

1

1

0

1

1

1

0

Example of exclusive OR
:
x = 75
y = 64
z = x ^ y
x = 1 0 0 1 0 1 1
y = 1 0 0 0 0 0 0
z = 0 0 0 1 0 1 1
hence, the value of
z=11
Bitwise
right shift ( >> )
Right shift operator
shifts each bit in its left operand to the right. The number of places the bits
are shifted depends on the number following the operator i.e. its right
operand.
In simple meaning of
bitwise right shift as :
insertion(zero) >
deletation
Example of right shift
operator :
x = 15
y = x >> 2
[x=15 before right
shifting ] 0000
0000 0000 1111
[y = x >> 2
during right shifting] 000000
0000 0000 1111
[y = x >> 2 after
right shifting] 0000 0000 0000 0011
so now value of y=3.
Left
Shift operator ( << )
This is similar to the
right shift operator, the only difference being that the bits are shifted to
the left, and for each shifted, a 0 is added to the right of the number.
Following structure shows it :
deletatio
>
insertion(zero)
Example of right shift
operator :
x = 15
y = x << 2
[x=15 before right
shifting ]
0000 0000 0000 1111
[y = x << 2
during right shifting] 0000
0000 0000 111100
[y = x << 2 after
right shifting] 0000 0000
0011 1100
so now value of y=60.
One's
complement ( ~ ) or Tilde
It is reverse the bit
i.e. if bit is 0 then its return 1 and when bit is 1 it is return 0.
example of tilde:
x = 15
y = ~ x
(15)_{10} = 0000 0000 0000 1111
y = ~ x
1111 1111 1111 0000
hense, 65535  15 =
65520.
so the value of y is
65520.
3.
Arithmetic Operator
Arithmetic operators
are special mathematical symbol which do all arithmetical calculation of the
programs. Following table display the operators and their works:
Name of operators

Symbol

works

example

Addition operator

+

Add the numbers

sum=7+8+1=16

Subtract operator



Subtraction of
numbers

sub=10050=50

Multiply operator

*

Multiple of
numbers

muti=8*9=72

Modulus operator

%

Find the reminder
of numbers

mod=45%40=5

Division operator

/

Find the division of numbers

div=45/40=1

4.Realational
Operator
When we write
program, many time we requirement to comparison of two or more data, in that
case we uses relational operators. There are following relational operators as
following :
Operators
Name
> Greater than
< Less than
= Equals
to
>= Greater
than equals to
<= Less than equals to
<= Less than equals to
!= Not equals
to
The syntax of
relational expression as :
<data
value 1>Relational operator<data value 2>
Example :
10 >= 5
50 <= 1
0 != 0
5. Sizeof operator
Sizeof operator
calculate the size of data i.e. how many bit a specific data having.
Syntax of sizeof
operator :
printf("<format
string>",sizeof<(data type variable)>);
/*Program to
sizeof operator*/
#include<stdio.h>
#include<conio.h>
void main()
{
int x=10;
clrscr();
printf("\nSize
of x is %d",sizeof(x));
getch();
}
Output of above
program :
Size of x is
2
We read in data type chapter that an int allocate only 2 byte
in memory,Hence, x = 2.
6.Increment and Decrement operators
Increment operators (++)
·
Increment operators are increase the value of subsequent. value may be
increase according to the programmer.
·
Increment operator are two types as follows :
1. Post increment
2. Pre increment
Decrement operators (  )
·
decrement operators decrease the value to one, two and so on.
·
As like Increment operators, decrement operators are also two type as
:
1. Post decrement
2. Pre decrement
Before we more discuss about increment and decrement operator, let
understand some expression; that's are using in all operators.
Now some issues of pre and post increment and decrement, we will discuss after solve following programming :
Now some issues of pre and post increment and decrement, we will discuss after solve following programming :
x = 5 x = 5 x = 5
x = x+1 ++x x++
x = 6 x = 6 x=5
In above program u
notice that value of x increase to one in all three expression but after the
increasing one, the final value of x in not same, third box result is differ to
another two boxes. Now you know that c operators are mostly three types, ++ and
 operators are Unary operators.
Post increment or decrement are lowest precedence so it is solve at the end of program. Hence above program in third box first value of x is print i.e. 5 after, it is increase.
Unary operators are solve right to left.
Post increment or decrement are lowest precedence so it is solve at the end of program. Hence above program in third box first value of x is print i.e. 5 after, it is increase.
Unary operators are solve right to left.
Q.1 Solve the expression in C language
compiler ,assuming x,z are integer variables:
z
= x++ + x++
where
x=7
Ans.
stepwise evaluation of this expression is shown below :
z = x++ + x++ + ++x
//post increment of x=2
z = x + x + ++x
//++x increase the value of x one so x=8
/*Now all pre and post increment/decrement are solved so we
write the the expression in normal mathematical expression*/
z = x + x + x
//put the current value of x i.e. 8
z = 8 + 8 + 8
z = 24
syntax : x=current valuepost increment/decrement
so x = 8 + 2
x = 10
Q.2 Solve the following expression
:
z
= ++x + y  ++y  x  x  ++y  x
where
x = 7
y = 3
Ans.
z=++x + y  ++y  x  x  ++y  x
/* post decrement of x=3 and
post decrement of y=1 */
z= ++x + y  ++y  x  x  ++y  x
/* its unary operator so we solve it from
right to left*/
z=++x + y  ++y  x  x  y  x
//now y=3+1=2
z=++x + y  y  x  x  y  x
//now y=2+1=1
z=x + y  y  x  x  y  x
//now x=7+1=8
/*now all increment and decrement operators
all solved so we put the current value of x
and y.*/
z= 8 + (1)  (1) 8  8  (1)  8
z= 8  1 + 1  8  8 + 1  8
z=  16 + 1
z= 15
x=83=5
y=11=2
Related some increment or decrement operators exercise:
Q.3 solve the following equations:
z = x++ + ++y  x + y
where x = 7 and
y = 9
hint:(For your crosschecking, answer is x=7, y=9 and z=18).
Q.4 solve the following equations:
z = x++ * y++ / ++x  y % x++
where x = 5 and
y = 2
hint:(For your crosschecking, answer is x=8, y=2 and z=0).

Q.3 answer with explanation :
z = x++ + ++y  x + y
where x = 7 and
y = 9
Ans:
post decrement of x = 1
post increment of x = 1
z = x + ++y  x + y
z = x + ++y  x + y // now y = 91 = 8
z = x + y  x + y // now y = 8+1 = 9
// now put the value of x and y
z = 7 + 9  7 + 9
z = 9 + 9
z = 18
Hence, our final answer will be:
x = 7  1 + 1 = 7
y = 9
z = 18
7.Comma operator
Comma operator ( , )
·
Evaluate of comma operator Left
to right.
·
Uses of comma operator as following :
1. Multiples declaration
2. Multiples initialization
3. Multiples variation
4. Multiples statement
·
Example of comma operator
1. int x=0,y=1,z=2;
2. for(x=0 , y=1, z=2 ; condition1 ,condition2 ;increment/decrement)
8.Typecast operator
The type cast operator is very important in C. Cast operator uses in
convert one data type to another data types. Type casting may be two types:
1. Implicit type cast
2. Explicit type cast
Implicit type cast
In C, implicit type cast are automatically handled by compiler i.e. when
two or more data types are getting execution then the final datatype will be
that data type as it is declared, i.e it is not depend on conversion of data
type.
It is clear understand by example as:
#include<stdio.h>
#include<conio.h>
void main()
{
int i,j;
float f;
double d;
i=d*f+f*j;
}
what you think, what will be data type of i?
it is double!! No, right answer is int. You see in program that double has high priority or
precedence of float and int, so result of data type will be comes in double but when result is assign in i,
it will be convert in int because i is declared as int. It is implicit type casting.
Explicit type cast
An explicit type cast is a cast that we should specify invoke with either
the cast. The compiler does not automatically invoke to resolve the data type
conversion.
Let's understand explicit with example:
/*A student marks of three subject as m1,m2,m3 and calculate
percentage(per)*/
#include<stdio.h>
#include<conio.h>
void main()
{
int m1=70,m2=70,m3=100,total;
float per;
total=m1+m2+m3;
per=total/300*100;
printf("%f",per);
}
output: 0.000000
Surprise, let's explain to me, it is a common type cast mistake, look at per=total/300*100; statement. In this statement first of all total/300 will be solve so total(240) and 300 are int hence 240/300 will be produce a float value so result is 0.000000. These mistake may me solved by three ways as:
1. We mention type cast in above program as:
/*demonstration of type casting*/
#include<stdio.h>
#include<conio.h>
void main()
{
int m1=70,m2=70,m3=100,total;
float per;
total=m1+m2+m3;
per=(float)total/300*100;
printf("%f",per);
}
output: 80.000000
2. We used total as float variable.
#include<stdio.h>
#include<conio.h>
void main()
{
int m1=70,m2=70,m3=100;
float per,total;
total=m1+m2+m3;
per=total/300*100;
printf("%f",per);
}
output: 80.000000
3. we convert int to float to the 300 by adding decimal portion.
#include<stdio.h>
#include<conio.h>
void main()
{
int m1=70,m2=70,m3=100,total;
float per;
total=m1+m2+m3;
per=total/300.0*100;
printf("%f",per);
}
output: 80.000000
9.Ternary operator
Main features of ternary operators as
follows :
·
There are three operand.
·
It works from left to right
·
Example of ternary operator is conditional operator. Symbol of
conditional operator : condition ? True_parts : False_parts
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