OPERATORS
OPERATORS IN .NET
An operator is a symbol that tells
the compiler to perform specific mathematical or logical manipulations. C# has
rich set of built-in operators and provides the following type of operators:
- Arithmetic Operators
- Relational Operators
- Logical Operators
- Bitwise Operators
- Assignment Operators
- Misc Operators
This tutorial explains the
arithmetic, relational, logical, bitwise, assignment, and other operators one
by one.
Arithmetic
Operators
Following table shows all the
arithmetic operators supported by C#. Assume variable A holds 10 and
variable B holds 20 then:
Operator
|
Description
|
Example
|
+
|
Adds two operands
|
A + B = 30
|
-
|
Subtracts second operand from the
first
|
A - B = -10
|
*
|
Multiplies both operands
|
A * B = 200
|
/
|
Divides numerator by de-numerator
|
B / A = 2
|
%
|
Modulus Operator and remainder of
after an integer division
|
B % A = 0
|
++
|
Increment operator increases
integer value by one
|
A++ = 11
|
--
|
Decrement operator decreases
integer value by one
|
A-- = 9
|
Relational
Operators
Following table shows all the
relational operators supported by C#. Assume variable A holds 10 and
variable B holds 20, then:
Operator
|
Description
|
Example
|
==
|
Checks if the values of two
operands are equal or not, if yes then condition becomes true.
|
(A == B) is not true.
|
!=
|
Checks if the values of two
operands are equal or not, if values are not equal then condition becomes
true.
|
(A != B) is true.
|
>
|
Checks if the value of left
operand is greater than the value of right operand, if yes then condition
becomes true.
|
(A > B) is not true.
|
<
|
Checks if the value of left
operand is less than the value of right operand, if yes then condition
becomes true.
|
(A < B) is true.
|
>=
|
Checks if the value of left
operand is greater than or equal to the value of right operand, if yes then
condition becomes true.
|
(A >= B) is not true.
|
<=
|
Checks if the value of left
operand is less than or equal to the value of right operand, if yes then
condition becomes true.
|
(A <= B) is true.
|
Logical
Operators
Following table shows all the
logical operators supported by C#. Assume variable A holds Boolean value
true and variable B holds Boolean value false, then:
Operator
|
Description
|
Example
|
&&
|
Called Logical AND operator. If
both the operands are non zero then condition becomes true.
|
(A && B) is false.
|
||
|
Called Logical OR Operator. If any
of the two operands is non zero then condition becomes true.
|
(A || B) is true.
|
!
|
Called Logical NOT Operator. Use
to reverses the logical state of its operand. If a condition is true then
Logical NOT operator will make false.
|
!(A && B) is true.
|
Bitwise
Operators
Bitwise operator works on bits and
perform bit by bit operation. The truth tables for &, |, and ^ are as
follows:
p
|
q
|
p
& q
|
p
| q
|
p
^ q
|
0
|
0
|
0
|
0
|
0
|
0
|
1
|
0
|
1
|
1
|
1
|
1
|
1
|
1
|
0
|
1
|
0
|
0
|
1
|
1
|
Assume if A = 60; and B = 13; then
in the binary format they are as follows:
A = 0011 1100
B = 0000 1101
-----------------
A&B = 0000 1100
A|B = 0011 1101
A^B = 0011 0001
~A = 1100 0011
The Bitwise operators supported by
C# are listed in the following table. Assume variable A holds 60 and variable B
holds 13, then:
Operator
|
Description
|
Example
|
&
|
Binary AND Operator copies a bit
to the result if it exists in both operands.
|
(A & B) = 12, which is 0000
1100
|
|
|
Binary OR Operator copies a bit if
it exists in either operand.
|
(A | B) = 61, which is 0011 1101
|
^
|
Binary XOR Operator copies the bit
if it is set in one operand but not both.
|
(A ^ B) = 49, which is 0011 0001
|
~
|
Binary Ones Complement Operator is
unary and has the effect of 'flipping' bits.
|
(~A ) = 61, which is 1100 0011 in
2's complement due to a signed binary number.
|
<<
|
Binary Left Shift Operator. The
left operands value is moved left by the number of bits specified by the
right operand.
|
A << 2 = 240, which is 1111
0000
|
>>
|
Binary Right Shift Operator. The
left operands value is moved right by the number of bits specified by the
right operand.
|
A >> 2 = 15, which is 0000
1111
|
Assignment
Operators
There are following assignment
operators supported by C#:
Operator
|
Description
|
Example
|
=
|
Simple assignment operator,
Assigns values from right side operands to left side operand
|
C = A + B assigns value of A + B
into C
|
+=
|
Add AND assignment operator, It
adds right operand to the left operand and assign the result to left operand
|
C += A is equivalent to C = C + A
|
-=
|
Subtract AND assignment operator,
It subtracts right operand from the left operand and assign the result to
left operand
|
C -= A is equivalent to C = C - A
|
*=
|
Multiply AND assignment operator,
It multiplies right operand with the left operand and assign the result to
left operand
|
C *= A is equivalent to C = C * A
|
/=
|
Divide AND assignment operator, It
divides left operand with the right operand and assign the result to left
operand
|
C /= A is equivalent to C = C / A
|
%=
|
Modulus AND assignment operator,
It takes modulus using two operands and assign the result to left operand
|
C %= A is equivalent to C = C % A
|
<<=
|
Left shift AND assignment operator
|
C <<= 2 is same as C = C
<< 2
|
>>=
|
Right shift AND assignment
operator
|
C >>= 2 is same as C = C
>> 2
|
&=
|
Bitwise AND assignment operator
|
C &= 2 is same as C = C &
2
|
^=
|
bitwise exclusive OR and
assignment operator
|
C ^= 2 is same as C = C ^ 2
|
|=
|
bitwise inclusive OR and
assignment operator
|
C |= 2 is same as C = C | 2
|
Miscellaneous
Operators
There are few other important
operators including sizeof, typeof and ? : supported by C#.
Operator
|
Description
|
Example
|
sizeof()
|
Returns the size of a data type.
|
sizeof(int), returns 4.
|
typeof()
|
Returns the type of a class.
|
typeof(StreamReader);
|
&
|
Returns the address of an
variable.
|
&a; returns actual address of
the variable.
|
*
|
Pointer to a variable.
|
*a; creates pointer named 'a' to a
variable.
|
? :
|
Conditional Expression
|
If Condition is true ? Then value
X : Otherwise value Y
|
is
|
Determines whether an object is of
a certain type.
|
If( Ford is Car) // checks if Ford
is an object of the Car class.
|
as
|
Cast without raising an exception
if the cast fails.
|
Object obj = new
StringReader("Hello");
StringReader r = obj as
StringReader;
|
Operator
Precedence in C#
Operator precedence determines the
grouping of terms in an expression. This affects evaluation of an expression.
Certain operators have higher precedence than others; for example, the
multiplication operator has higher precedence than the addition operator.
For example x = 7 + 3 * 2; here, x
is assigned 13, not 20 because operator * has higher precedence than +, so the
first evaluation takes place for 3*2 and then 7 is added into it.
Here, operators with the highest
precedence appear at the top of the table, those with the lowest appear at the
bottom. Within an expression, higher precedence operators are evaluated first.
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
|
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