OPERATORS IN JAVA

OPERATORS IN JAVA

Java provides a rich set of operators to manipulate variables. They are

• Arithmetic Operators
• Relational Operators
• Bitwise Operators
• Logical Operators
• Assignment Operators
• Misc Operators

The Arithmetic Operators:

• Arithmetic Operators are used to perform some mathematical operations like addition, subtraction, multiplication, division, and modulo (or remainder).
• Arithmetic operators are used in mathematical expressions in the same way that they are used in algebra. The following table lists the arithmetic operators:
• Assume integer variable A holds 10 and variable B holds 20 then:

Examples

Operator	Description	Example
+	Addition - Adds values on either side of the operator	A + B will give 30
-	Subtraction - Subtracts right hand operand from left hand operand	A - B will give -10
*	Multiplication - Multiplies values on either side of the operator	A * B will give 200
/	Division - Divides left hand operand by right hand operand	B / A will give 2
%	Modulus - Divides left hand operand by right hand operand and returns remainder	B % A will give 0
++	Increment - Increase the value of operand by 1	B++ gives 21
--	Decrement - Decrease the value of operand by 1	B-- gives 19

The Relational Operators:

• Whenever we need to compare the results of two expressions or operands in a program then the equality and relational operators are used to know whether an operand is equal, not equal, greater than, less than to another operand.
• There are following relational operators supported by Java language
• Assume variable A holds 10 and variable B holds 20 then:

Examples

Operator	Description	Example
==	Checks if the value of two operands are equal or not, if yes then condition becomes true.	(A == B) is not true.
!=	Checks if the value 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.

The Bitwise Operators:

• Java defines several bitwise operators which can be applied to the integer types, long, int, short, char, and byte.
• In Java the bitwise and bit shift operators are used to manipulate the contents of variables at a bit level according to binary format.
• Bitwise operator works on bits and perform bit by bit operation. Assume if a = 60; and b = 13; 
• Now in binary format they will be as follows:

a = 0011 1100

b = 0000 1101

-----------------

a&b = 0000 1100

a|b = 0011 1101

a^b = 0011 0001

~a  = 1100 0011

Assume integer variable A holds 60 and variable B holds 13 then:

Examples:

Operator	Description	Example
&	Binary AND Operator copies a bit to the result if it exists in both operands.	(A & B) will give 12 which is 0000 1100
|	Binary OR Operator copies a bit if it exists in eather operand.	(A | B) will give 61 which is 0011 1101
^	Binary XOR Operator copies the bit if it is set in one operand but not both.	(A ^ B) will give 49 which is 0011 0001
~	Binary Ones Complement Operator is unary and has the efect of 'flipping' bits.	(~A ) will give -60 which is 1100 0011
<<	Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.	A << 2 will give 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 will give 15 which is 1111
>>>	Shift right zero fill operator. The left operands value is moved right by the number of bits specified by the right operand and shifted values are filled up with zeros.	A >>>2 will give 15 which is 0000 1111

The Logical Operators:

• Logical operators return a true or a false value based on the state of the variables i.e. the operations using conditional operators are performed between the two boolean expressions.
• The following table lists the logical operators:
• Assume boolean variables A holds true and variable B holds false then:

Examples:

Operator	Description	Example
&&	Called Logical AND operator. If both the operands are non zero then then condition becomes true.	(A && B) is false.
||	Called Logical OR Operator. If any of the two operands are non zero then 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.

The Assignment Operators:

• Assignment operator is the most common operator almost used with all programming languages
• There are following assignment operators supported by Java language:

Examples:

Operator	Description	Example
=	Simple assignment operator, Assigns values from right side operands to left side operand	C = A + B will assigne 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

Misc Operators

There are few other operators supported by Java Language.

Conditional Operator ( ? : ):

• Conditional operator is also known as the ternary operator. This operator consists of three operands and is used to evaluate boolean expressions. 
• The goal of the operator is to decide which value should be assigned to the variable. The operator is written as :

variable x = (expression) ? value if true : value if false

Example:

public class Test {    public static void main(String args[]){       int a , b;       a = 10;       b = (a == 1) ? 20: 30;       System.out.println( "Value of b is : " +  b );       b = (a == 10) ? 20: 30;       System.out.println( "Value of b is : " + b );    } }

Output:

Value of b is : 30 Value of b is : 20

instanceOf Operator:

• Java provides a run-time operator instanceof to compare a class and an instance of that class. This operator " instanceof" compares an object to a specified class type.
• This operator is used only for object reference variables. The operator checks whether the object is of a particular type(class type or interface type). instanceOf operator is wriiten as:

( Object reference variable ) instanceOf  (class/interface type)

If the object referred by the variable on the left side of the operator passes the IS-A check for the class/interface type on the right side then the result will be true. 

Example:

String name = = 'James'; boolean result = s instanceOf String;  // This will return true since name is type of String

This operator will still return true if the object being compared is the assignment compatible with the type on the right. 

Example:

class Vehicle {} public class Car extends Vehicle {    public static void main(String args[]){       Vehicle a = new Car();       boolean result =  a instanceof Car;       System.out.println( result);    } }

Output:

true

Precedence of Java Operators:

• In Java, Operator Precedence is an evaluation order in which the operators within an expression are evaluated on the priority bases.
• Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others;

Unary Operators

• The unary operators requires only one operand to perform different kind of operations such as increasing/decreasing a value, negating an expression, or inverting a boolean value.
• 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 precedenace operators will be evaluated first.

Category	Operator	Associativity
Postfix	() [] . (dot operator)	Left to right
Unary	++ - - ! ~	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