Operator
Kinds of Operator
Precedence of Operator
Type Casting

Operator
 Decide the semantics of expression
 Meaning of operator given in language system

Kinds of Operator
Arithmetic Op. : + - * / %
Relational Op. : > >= < <= == !=
Logical Op. : && || !
Inc/Dec Op. : ++ --
Bit Op. : & | ^ ~ << >> >>>
Operators of Java
Conditional Op. : ?:
Assign Op. : = += -= *= /= %= &= ^= |= >>= <<= >>>=
Casting Op. : (Data Type)
Array Op. : []
Method Op. : () .
instanceof Op. : instanceof

Arithmetic Operator
 Operator for arithmetic operation
 Single term operator : +, -
 Binary term operator : +, -, *, /, %
 [ArithmeticOperators.java]
x = -5 ;
x = -(-5) ;
x = -(3-5) ;

Arithmetic Operator
 Real type operation
 Floating point discription and operation: IEEE754
Standard
 underflow, overflow
 Infinitive arithmetic
 java.lang.Float, java.lang.Double,
POSITIVE_INFINITY, NEGATIVE_INFINITY constant
 NaN(Not a Number)

Arithmetic Operator
 Add, Substract
 Multiply, Divide
x y x+y x-y
+I.F +I.F +I.F NaN
+I.F - I.F NaN +I.F
- I.F +I.F NaN - I.F
- I.F - I.F - I.F NaN
NaN +I.F NaN NaN
x y x/y x%y
Finite 0.0  I.F NaN
Finite I.F 0.0 
0.0 0.0 NaN NaN
I.F Finite  I.F NaN
I.F I.F NaN NaN
 [InfinityArithmetic.java]

Relational Operator
 Compare two value
 Result : true or false
 Expression include relational operator
 for, while, ...
 Operator
 , , , , , 
 precedence 
 [RelationalOperators.java]
a > b + c ===> a > (b + c)
b == x < y ===> b == (x < y)

Conditional Operator
 Conditional Logical Relationship of two
operands
 Operator
 ! , && , ||
 [LogicalOperators.java]
a < b && b < c
1 2
3

Increment & Decrement Operator
 Operator
 ++, --
 Prefix operator
 Postfix operator
 Cannot use at expression, only at variable
 Cannot apply at real type
 [IncDecOperators.java]
n = 1;
x = ++n; // x=2, n=2
n = 1;
x = n++; // x=1, n=2
(a + b)++ // error

Bitwise Operator
 Operator
 &, |, <<, >>, >>>, ^, ~
 Operand should be integer type
 Precedence
Operator Precedence
~
<< >> >>>
&
^
|
(H)
(L)

Bitwise Operator
 Bitwise AND
 10012 & 00112 = 00012
 To extract the special area in variable by masking that
area
 Bit OR
 10012 | 00112 = 10112
 Exclusive AND
 10012 ^ 00112 = 10102
 1’s Complement
 ~ 000010102 = 111101012
 [BitOperators.java]

Bitwise Operator
 Bitwise Shift Operator
 Shift lefe(<<)
 Shift right(>>)
 Unsigned shift right(>>>)
 Give this operator because Java does not support unsigned integer.
 [ShiftOperators.java]
x << y = x * 2y
x >> y = x / 2y

The Conditional Operator
 Operator
 Expr1 ? Expr2 : Expr3 (3 Terms Operator)
 [ConditionalOperator.java]
 [PrintTenItem.java]
m = a > b ? (c > a ? c : a) : (c > b ? c : b) ;
max = x > y ? x : y ;
if (x > y) max = x;
else max = y;

Assignment Operators
 Operator
 Arithmetic operator : + - * / %
 Bitwise operator : & | ^ << >> >>>
 [AssignmentOperators.java]
Expr 1 = Expr 1 op Expr2 Expr1 op= Expr 2
x = x * y + 1; x *= y + 1;
x = x * (y+1)
sum = sum + i ; sum += i ;

Cast Operator
 Data Type Casting Operator
 Cast operator : ( , )
 [CastOperator.java]
(Data Type) 식
(int) 3.75 ===> 3
(float) 3 ===> 3.0
(float) (1 / 2) ===> 0.0
(float)1/2 ===> 0.5

Operator Precedence
Operator Association Precedence
() [] .
! ~ ++ -- + - (Data Type)
* / %
+ -
<< >> >>>
< <= > >= instance
== !=
&
^
|
&&
||
? :
= += -= *= /= %= &= ^= |= <<= >>= >>>=
Left Assoc. (High)
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc.
Left Assoc. (Low)