operators.ppt

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)

operators.ppt

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