Binary operators
are the operators which works on two operands at a time.
E.g. z=x+y;
Here, + is binary
operator.
X and y are
operands.
So, “+” operator
works on two operands (Here x and y) at a time. Unlike binary operators, unary
operator works on only one operand at a time.
Note that, unary
operators have higher precedence than arithmetic operators. Another main
difference between unary and binary operator is the associativity. The
associativity of unary operator is from right to left, whereas the
associativity of binary operator is from left to right. We will see the concept
of associativity later on. In C you can use the following unary operators.
1) Unary minus (-):
Unary minus change the sign of operand it preceding.
E.g. -786, -temp, 5E-5 etc.
2)Unary not or Logical not or Negation:
It is used to negates the condition. The following examples should better
clarify this concept.
E.g. if(!TRUE) is
same as
if(FALSE)
Similarly,
if(!FALSE) is same as
if(TRUE)
Where TRUE is a
symbolic constant having nonzero value (E.g. 100,-100, 1 etc.), and FALSE is a
symbolic constant having value 0. Remember that, any nonzero value is treated as true value in C and 0 is treated as
falsity.
Consider an
example,
!(ZZ>=5) is same as
ZZ<5
3)Increment and decrement operator (++ and --):
Increment operator increment the value of the variable by 1, and the decrement
operator decrease the value of the variable by 1.
E.g. i=5;
i++;
Increments the
value of I by 1. So, after evaluation of the statement i++, I contains a value
of 6. instead of i++, you can write ++I also. But there is slight difference
between the two. We will see it later on.
Similarly, we can
decrement the value of the variable by 1 using:
E.g. i=5;
i--;
Decrement the value
of I by 1. So, after evaluation of this statement i contain a value of 4. Here
also you can write --i instead of i--.
4)Address of operator (&): The
address of operator is used to find the address of the variable it precedes.
E.g. printf(“The
address of the variable x=%u”,&x);
Note: You can use %p or %u
format specifier for printing the addresses of the variables.
Consider the
following example,
Program 6:
#include <stdio.h>
#include <conio.h>
void main()
{
int x;
clrscr();
printf(“\nThe address
of the variable x is=%u”,&x);
printf(“\nThe address
of the variable x is=%p”,&x);
getch();
}
Run the program,
you will get the following output (in your case it may be different, because
the compiler maqy select any available address as well.)
Output:
#-------------------------------------------------------------------------------#
The address of the variable x is=65524
The address of the variable x is=FFF4
#-------------------------------------------------------------------------------#
What?
Two different outputs for same variable? Absolutely nooooo. Every variable can
have only one unique address assigned by the compiler at run time. Then what is
the mystery behind this output? Actually, the address we have printed using %p
format specifier is hexadecimal equivalent of its address 65524.So, both 65524
and FFF4 represents same location in the memory. Now, it is totally up to you
to decide whether you want to print your variable addresses using decimal
notation or hexadecimal notation. Try using %x or %X format specifier to print
the address of the variable x. You will get the same output as produced by %p
but %X will print the output in upper case letter whereas %x will print the
output in lowercase letters.
4) sizeof(): sizeof() operator
returns the size of its operands in bytes.
E.g. sizeof(x) ;
Gives the number of
bytes allocated to the data type of x. Consider the following example.
Program 6:
#include <stdio.h>
#include <conio.h>
void main()
{
char a;
int b;
float c;
clrscr();
printf(“\nThe number
of bytes reserved for character is=%d”,sizeof(a));
printf(“\nThe number
of bytes reserved for integer is=%d”,sizeof(b));
printf(“\nThe number
of bytes reserved for float is=%d”,sizeof(c));
getch();
}
Run
the program and you will get following output.
#-------------------------------------------------------------------------------#
The number of bytes reserved for character is=1
The number of bytes reserved for integer is=2
The number of bytes reserved for float is=4
#-------------------------------------------------------------------------------#
In
above program we use %d to print the size of the variables as the sizeof()
returns the size of operands in an integer format.
Now,
try to run the following code.
Program 6:
#include <stdio.h>
#include <conio.h>
void main()
{
clrscr();
printf(“\nThe number
of bytes reserved for float is=%d”,sizeof(3.14));
getch();
}
Run
it, and observe the unexpected output.
#-------------------------------------------------------------------------------#
The number of bytes reserved for float is=8
#-------------------------------------------------------------------------------#
In
the previous program the size reported by the compiler for float is 4 bytes and
now it report 8 bytes! How?
Note: A floating point number is specified by the float
keyword in the C language. Floating point numbers can be suffixed with the
letter f or F to specify float explicitly. A floating point number without suffix is
double by default.
Therefore the correct
version of the above program is:
#include <stdio.h>
#include <conio.h>
void main()
{
clrscr();
printf(“\nThe number
of bytes reserved for float is=%d”,sizeof(3.14F));
getch();
}
Run
it, and you will get the expected output.
#-------------------------------------------------------------------------------#
The number of bytes reserved for float is=4
#-------------------------------------------------------------------------------#
Note: if sizeof() is being applied to the
type then parenthesis () are required, otherwise they are optional.
So,
the following code is valid one.
Program 9:
#include <stdio.h>
#include <conio.h>
void main()
{
clrscr();
printf(“\n%d”,sizeof 3);
getch();
}
But, this is invalid.
#include <stdio.h>
#include <conio.h>
void main()
{
clrscr();
printf(“\n%d”,sizeof int);
getch();
}
Now, consider the another example using
sizeof which will produce the unexpected output.
#include <stdio.h>
#include <conio.h>
void main()
{
clrscr();
printf(“\n%d”,sizeof (‘a’));
getch();
}
Run
the program now.
Output:
#-------------------------------------------------------------------------------#
2
#-------------------------------------------------------------------------------#
Remember
that the character constants in C are of type int, so sizeof(‘a’) is
equal to sizeof(int).
6) Cast unary
operator: This
operator is used to change the type of the variable, constant or expression
explicitly.
E.g.
(int)3.14159;
Change
the value of operand to 3.
