OOP WITH JAVA CHAPTER 2 (NEW 2018)
OBJECT ORIENTED PROGRAMMING WITH JAVA
CHAPTER 2
Primitive data type
\U0000 \UFFFF
Char
Char C=”A”
Escape sequence
“My School”
“\”
Char table
=”\t”;
Nul=”1000”;
Slash=”\\”;
Boolean
Boolean data
type has two possible values either
True or
false
Ø By default it is false.
Boolean flag =true;
System.out.println(flag);
Short
Short data
type can have value from [32768,32767];
By default
it is zero
Short temp =
100;
System.out.println(tem);
Integer
Int data
type can have value from -2^31 to [2^31-1]
Long
Long data
type can have value from
[-2^63,2^63-1]
Double
Double data
type has double precision 64-bit floating point.
default value =0.0
default value =0.0
Example
Double
number =-15.09;
System.out.println(number);
Float
Flot data
type is single precision
32 bit data
type.
Float num
=-15.9
Output
=-15.9.
Type
casting(conversion)
Int i=13
X
byte=I;//not allowed in java
Byte
b=(byte);
Primitive data type
Java support
eight basic type known as primitive data types. the primitive types includes a
Boolean type,a character type ,four integer types ,and two floating point types
differ in the number of bits that represent them and therefore in the range of
numbers they can represent.
Variable and type of
variable
Named memory
location that can change it self value during the execution of program.
int a=65;
Types
1.local variable
2.Instant variable
3.Static variable
4.Constant variable
Local variable‘‘A local variable
which is declared inside the method is called local variable’’ .local variable
are only visible within the relevant method, constructor, or block.
There is no
default value for local variables.
Constant variable
Constant
variable declares with const keyword and can be used with primitive data types.
Constant are set at compile time it self and assigned for value type only.
Static variable
Static
variable is a property of a class rather then the instance of class. If can be
assigned for refrence types and set of run time.
1. It is a variable which belongs to the
class not to the instance (Object).
2. Static variable are initialized only
once at the start of execution.
3. Single copy to be shared by all
instances.
4. Static variable can be accesed by the
name.
Syntax
<Class
Name><Variable Name>
Instance variable:.
A variable
which is declared insight the class but outside the method.
public static void main(string[]args){
}
Public
static void student(){method
Int
rollno=0;
String
name=0;
Public void
main add new () {
}
Operators
1) Assignment operator.
2) Arithmetic operator.
3) Logical operator.
4) Relational operator.
5) Bitwise operator.
Unary:.
Int i-5;
operand
i --;
-i;
Binary:.
a=3;
b=4;
Ternary:.
Ternary
operator is short hand of
if-then-else.
var=Expression?Expression1:Expression2;
Program:.
int dayofFeb=28;
String result;
result=(dayofFeb==29)?"leap year":"Not leap year";
System.out.println(result);
Relational
operator
A relational
operators compairs two values and determines the relation ship between them.
a=5,b=3 (a==b)//0
==checks the
value of two operands are equal or not.if yes the condition become true.
|=checks if
value of two operands are equal or not.and return true if values are unequal.
a=5,b=3
a>b if
value of left operand is greater then right operand it return 1.
a<b check
if the value of left operand is greater is less then value of right operand it
returns true.
Program
package
javapractice2;
public class
Javapractice2 {
public static void main(String[] args) {
int a=10;
int b=5;
System.out.println("a+b="+a+b);
System.out.println("a*b"+a*b);
System.out.println("a%b"+a%b);
System.out.println("a/b"+a/b);
}
}
Output
run:
a+b=105
a*b50
a%b0
a/b2
BUILD SUCCESSFUL
(total time: 0 seconds)
Assignment operator
Assignment
operator assigns value from right side to left side
operand.
a=5*2+2;
a=s;
b=3;
+= a+=b;//a=a+b
Arithmetic operator
Arithmetic
operators are used in the same way that they are used in algebra.
+;a+b
(addition)
-;a-b(subtraction)
*;a*b(multiply)
/;a/b(divide
left side operand to right side)
%;a%b(return
remainder after division)
Logical operator.
Logical
operators are known as Boolean operators.logical operator on Boolean values and
produces a Boolean as a result.
Bitwise operator
1. AND( &)
2. OR (|)
3. NOT
Bitwise and&:.
Bitwise and
is a binary operator that compares corresponding bits of two operands.
Bitwise or|
Bitwise
operator perform bit by bit operations or gives 1 if either bit is 1
Bitwise not
It converts
the bit pattern .it is a unary operator.
Bitwise
Rightshift>>
Left
shift<<
Rightshift
Righty shift
operator shift a pattern of bits toward right by certain number of specified
bits.
A=000111100//00
R=a>>1;
R=30
Left shift(<<)
Left shifs a
pattern of bits towards left by specific number of times.
Int
x=0000100 //4
R=
x<<3;00100000 //
Unary
Increment operator
Increment
operator increases the value of operand by 1.
Int f=1;
f++;
post increment pre increment
x++
++x
Decrement operator
It decreases
the value of operand by 1.
Int
y=3;
y--;//y=3
y--;//y=3
post decrement pre
decrement
y-- --y
Auto boxing
Auto boxing
is the automatic conversion that a java compiler makes between primitive data
types and their corresponding wrapper classes.
Primitive Wrapper
Int
integer
Un boxing
The
automatic conversion of wrapper class object into relevant primitive data type
is called un boxing.
Integer
i=new integer (30);
Int j=I;
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