Java 2

 Java provides a rich set of operators to manipulate
variables. We can divide all the Java operators into the
following groups:

• Assignment Operator

•Arithmetic Operators

•Unary Operators

• Equality and Relational Operators

•Conditional (Logical) Operators

•Bitwise and Bit Shift Operators

(1) Assignment Operator

 Simple Assignment Operator
Syntax of using the assignment operator is:
<variable> = <expression>;

 Compound Assignment Operator
Syntax of using the compound assignment operator is:
operand operation= operand

Compound assignment operators :

Operator Example Equivalent Expression
+= x += y; x = (x + y);

-= x -= y; x = (x - y);

*= x *= y; x = (x * y);

/= x /= y; x = (x / y);

%= x %= y; x = (x % y);

&= x &= y; x = (x & y);

|= x != y; x = (x ! y);

^= x ^= y; x = (x ^ y);

<<= x <<= y; x = (x << y);

>>= x >>= y; x = (x >> y);

>>>= x >>>= y; x = (x >>> y);

(2) Arithmetic Operators
 The symbols of arithmetic operators are given in a table:

Symbol Name of the Operator Example

+ Additive Operator n = n + 1;

- Subtraction Operator n = n - 1;

* Multiplication Operator n = n * 1;

/ Division Operator n = n / 1;

% Remainder Operator n = n % 1;

 The "+" operator can also be used to concatenate (to join) the two strings
together.

 For example:
String str1 = "Concatenation of the first";
String str2 = "and second String";
String result = str1 + str2;

(3) Unary Operators
There are different types of unary operators :

 + Unary plus operator indicates positive value (however, numbers
are positive without this)
Ex : int number = +1;
 - Unary minus operator negates an expression
Ex : number = - number;
 ++ Increment operator increments a value by 1
Ex : number = ++ number;
 -- Decrement operator decrements a value by 1
Ex : number = -- number;
 ! Logical compliment operator inverts a boolean value

(4) Equality and Relational Operators

== Equal to a==b

!= Not equal to a!=b
> Greater than a>b

< Less than a<b

>= Greater than or equal to a>=b

<= Less than or equal to a>=b

(5) Conditional (Logical) Operators

Symbol Name of the Operator

& AND

&& Conditional-AND

| OR

|| Conditional-OR

! NOT

?: Ternary (shorthand for if-then-else statement)

ternary ("?:") operator

Java supports another conditional operator that is known as the ternary operator
"?:" and basically is used for an if-then-else as shorthand as

boolean expression ? operand1 : operand2;

If we analyze this diagram then we find that, operand1 is returned, if
the expression is true; otherwise operand2 is returned in case of false
expression.

Lets have an example implementing some Logical operators:

class ConditionalOperator
{

public static void main(String[] args)
{
int x = 5;
int y = 10, result=0;
boolean bl = true;
if((x == 5) && (x < y))
System.out.println("value of x is "+x);
if((x == y) || (y > 1))
System.out.println("value of y is greater than the value of x");
result = bl ? x : y;
System.out.println("The returned value is "+result);
}
}

Output

value of x is 5 is 5
value of y is greater than the value of x lue of y is greater than the value of x
The returned value is 5

(6) Bitwise and Bit Shift Operators
. There are different types of bitwise and bit shift operators available in
the Java language summarized in the table.


~ Unary bitwise complement ~op2

& Bitwise AND op1 & op2

| Bitwise inclusive OR op1 | op2

^ Bitwise exclusive OR op1 ^ op2

<< Signed left shift op1 << op2

>> Signed right sift op1 >> op2

>>> Unsigned right shift op1 >>> op2

I. Unary Bitwise Complement ("~") :
Lets use the table to understand bitwise complement
operation :

Operand Result

0 1
1 0
1 0
0 1

II. Bitwise AND (&) :

Lets understand the AND operations using truth table:

(AND)
A B Result
0 0 0
1 0 0
0 1 0
1 1 1

III. Bitwise inclusive OR ( | ) :
Lets understand the inclusive OR operations using truth
table:
(OR)
A B Result
0 0 0
1 0 1
0 1 1
1 1 1

IV. Bitwise exclusive OR (^) :
Lets understand the exclusive OR operations using truth
table:
A B Result
0 0 0
1 0 1
0 1 1
1 1 0

 Bit Shifts Operators:
I. Signed Left Shift ("<<") :

This diagram shows that, all bits of the upper position were shifted to the left by
the distance of 1; and the Zero was shifted to the right most position. Thus the
result is returned as 11100.

Another expression "2<<2"; shifts all bits of the number 2 to the left placing a
zero to the right for each blank place. Thus the value 0010 becomes 1000 or 8 in
decimal.

II. Signed Right Shift (">>") :

This diagram shows that, all bits of the upper position were shifted to the right
distance specified by 1; Since the sign bit of this number indicates it as a positive
number so the 0 is shifted to the right most position. Thus the result is returned as
00011 or 3 in decimal.

Another expression "2>>2"; shifts all bits of the number 2 to the right placing a
zero to the left for each blank place. Thus the value 0010 becomes 0000 or 0 in
decimal.

III. Unsigned Right Shift (">>>") :

For example, the expression "14>>>2"; shifts all bits of the
number 14 to the right placing a zero to the left for each blank
place Thus the value 1110 becomes 0011 or 3 in decimal.

Operator Precedence

Operators Precedence

array index & parentheses [] ( )
access object .
postfix expr++ expr--
unary ++expr --expr +expr -expr ~ !
multiplicative * / %
additive + -
bit shift << >> >>>
relational < > <= >=
equality == !=
bitwise AND &
bitwise exclusive OR ^
bitwise inclusive OR |
logical AND &&
logical OR ||
ternary ?:
assignment = += -= *= /= %= &= ^= |= <<= >>= >> >=

 Lets see an example that evaluates an arithmetic
expression according to the precedence order.

class PrecedenceDemo
{
public static void main(String[] args)
{
int a = 6;
int b = 5;
int c = 10;
float rs = 0;
rs = a + (++b)* ((c / a)* b);
System.out.println("The result is:" + rs);
}
}

 The expression "a+(++b)*((c/a)*b)" is evaluated from right
to left. Its evaluation order depends upon the precedence order of
the operators. It is shown below:

(++b) a + (++b)*((c/a)*b)
(c/a) a+ (++b)*((c/a)*b)
(c/a)*b a + (++b)*((c/a)* b)
(++b)*((c/a)*b) a + (++b)*((c/a)* b)
a+(++b)*((c/a)*b) a+(++b)*((c/a)*b)

Output

The result is:42.0

Java 2

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