Java Modifiers, Variables in addition to Operators
i) Modifiers inwards Java
ii) Java Variables
iii) Java operators
-----------------------------
i) Modifiers inwards Java
Modifiers are keywords that nosotros add together to those definitions to alter their meaning.
a) Access Modifiers
b) Non-Access Modifiers
--------------------------
a) Access Modifiers
We role access modifiers to define access command for classes, methods in addition to variables.
Four Access Modifiers
i) private
The mortal access modifier is accessible alone within class.
Ex:
private int a =100;
2) default
If nosotros don't specify whatever modifier hence it is treated equally default, this tin live accessible alone within package.
class Sample{
.
.
}
3) protected
The protected access modifier is accessible within package, exterior of the bundle but through Inheritance only.
protected course of teaching Sample{
.
.
}
4) public
public access modifier is accessible everywhere.
public course of teaching Sample {
.
.
}
---------------------------------------------------
b) Non Access Modifiers
1) static
static modifier is used practice classes, methods in addition to variables.
Ex:
static int a =10;
static void int add(){
.
.
}
2) concluding
final modifier for finalizing of classes, methods in addition to variables.
Ex:
final int a =100;
.
.
.
a=200; //Error
---------------
int a =100;
.
.
.
.
a =200;
------------------
3) abstract
abstract modifier is to practice abstract classes, abstract methods
ex:
abstract course of teaching Sample{
.
.
}
-------------------------------
ii) Java Variables
1) What is Variable?
A named retentiveness place to shop the temporary information within a program.
Two types of memories inwards Computer environment
a) Primary retentiveness (RAM)
b) Secondary retentiveness (HDD, DVD, USB movement etc...)
----------------------------
2) Declaration of Variables
Java supports Explicit annunciation of Variables.
Syntax in addition to Examples:
dataType variableName;
int a;
-------------
dataType variablename=value;
int b=20;
---------------
dataType variable1, Variable2, variable3;
int a, b, c;
-----------------
dataType variable1=value; variable2=value; varible3=value;
int a=10; b=20; c=30;
------------------------------------
3) Assign values to variables
a) Initialization
b) Reading
Ex:
int a=100; //Initialization
int a=10;
int b;
b=a; //Reading
---------------------------------
4) Variable Naming Restrictions
> Java variables are illustration sensitive,
> Java variable nurture should start amongst a missive of the alphabet or $ or _
Ex:
myvar(Correct)
MYVAR
$myvar
_myvar
myvar_1
--------------
1myvar(Incorrect)
*myvar
----------------
> Variable names should non check amongst Java keywords/Reserved words.
> Must live unique inwards the range of declaration.
> Variable names Must non overstep 255 characters.
-------------------------------------------
5) Types of Variables
Three types of variables inwards Java
a) Local variable(Local variable is declared inwards methods or blocks.)
b) Instance variable(Instance variables are declared inwards a course of teaching but exterior of a method or whatever block)
c) Class/Static variableA Variable that is declared equally static, It cannot live local.
----------------------------------
Example:
package xyza;
public course of teaching VariablesExample {
//a Variable is a Class/Static variable
static int a =100;
//mysalary variable is a Local variable.
public int salary(){
int mysalary =10000+2000+1500;
mysalary=mysalary + a;
furnish mysalary;
}
public static void original (String[]args){
//Instance variable
int b =200;
System.out.println(a);//100
System.out.println(b); //200
VariablesExample obj= novel VariablesExample();
System.out.println(obj.salary());
// i is a Local Variable
for (int i=1; i<=5; i++){
System.out.println(i);
System.out.println(a);
System.out.println(b);
}
}
}
----------------------------------
iii) Java Operators
Important Categories of Operators
a) Arithmetic Operators
b) Relational Operators
c) Assignment Operators
d) Logical Operators
-------------------------------
a) Arithmetic Operators
1) Addition + (for Addition, String concatenation)
2) Subtraction - (for Subtraction, Negation)
3) Multiplication *
4) Division /
5) Modules %
6) Increment ++
7) Decrement --
---------------------------
Example:
public course of teaching OperatorsExample {
world static void original (String [] args){
int a =10, b=5;
String c ="Selenium", d= "Testing";
System.out.println("Addition of a, b is: "+ (a+b));//Addition of a, b is: 15
System.out.println("Subtraction of a, b is: "+ (a-b));
System.out.println("Multiplication of a, b is: "+ (a*b));
System.out.println("Division of a, b is: "+ (a/b));
System.out.println("Modules of a, b is: "+ (a%b));
b=10;
a = ++b;
System.out.println(a);//11
b=10;
a = --b;
System.out.println(a);//9
}
}
---------------------------------------
b) Relational Operators
1) ==
2) !=
3) >
4) >=
5) <
6) <=
----------------------------------
Note: Relational Operators furnish Boolean / Logical result
Example:
public course of teaching OperatorsExample {
world static void original (String [] args){
int a =10, b=20;
System.out.println((a>b));//false
System.out.println((a>=b));//false
System.out.println((a==b));//false
System.out.println((a<b));//true
System.out.println((a<=b));//true
System.out.println((a!=b));//true
}
}
------------------------------------------------
d) Logical Operators
1) Logical Not Operator !
2) Logical And Operator &&
3) Logical Or Operators ||
Result Criteria
Not operator
--------------
Operand1 Operand2 Result
--------------------------------------
true true false
true false true
false true true
false false true
--------------------------------------
And operator
--------------
Operand1 Operand2 Result
--------------------------------------
true true true
true false false
false true false
false false false
--------------------------------------
Or Operator
Operand1 Operand2 Result
--------------------------------------
true true true
true false true
false true true
false false false
--------------------------------------
Example:
public course of teaching OperatorsExample {
world static void original (String [] args){
boolean a =true, b=false;
System.out.println(!(a && b));//true
System.out.println((a && b));//false
System.out.println((a || b));//true
}
}
--------------------------------------
public course of teaching OperatorsExample {
world static void original (String [] args){
int a =1000, b=500, c=7000;
if ((a>b) && (a>c)){
System.out.println("A is a Big Number");
}
else{
System.out.println("A is Not a Big Number");
}
}
}
--------------------------------------
c) Assignment Operators
1) Assignment Operator
=
a=10;
2) Add in addition to Assign +=
3) Subtract in addition to assign
4) Multiple in addition to assign
-------------------------------
Example:
public course of teaching OperatorsExample {
world static void original (String [] args){
int a =10;
System.out.println(a);//10
a+=10;
System.out.println(a);//20
a-=10;
System.out.println(a);//10
a*=10;
System.out.println(a);//100
}
}
-----------------------------------------------------------
Bitwise Operators
> Java defines several bitwise operators, which tin live applied to the integer types, Bitwise operator works
on bits in addition to performs bit-by-bit operation.
i) The bitwise & operator performs a bitwise AND operation.
ii) The bitwise ^ operator performs a bitwise exclusive OR operation.
iii) The bitwise | operator performs a bitwise XOR operation.
i) Modifiers inwards Java
ii) Java Variables
iii) Java operators
-----------------------------
i) Modifiers inwards Java
Modifiers are keywords that nosotros add together to those definitions to alter their meaning.
a) Access Modifiers
b) Non-Access Modifiers
--------------------------
a) Access Modifiers
We role access modifiers to define access command for classes, methods in addition to variables.
Four Access Modifiers
i) private
The mortal access modifier is accessible alone within class.
Ex:
private int a =100;
2) default
If nosotros don't specify whatever modifier hence it is treated equally default, this tin live accessible alone within package.
class Sample{
.
.
}
3) protected
The protected access modifier is accessible within package, exterior of the bundle but through Inheritance only.
protected course of teaching Sample{
.
.
}
4) public
public access modifier is accessible everywhere.
public course of teaching Sample {
.
.
}
---------------------------------------------------
Modifier | Within Class | Within Package | Outside of the Package (By Sub Class) | Outside of the Package |
private | Y | N | N | N |
default | Y | Y | N | N |
protected | Y | Y | Y | N |
public | Y | Y | Y | Y |
b) Non Access Modifiers
1) static
static modifier is used practice classes, methods in addition to variables.
Ex:
static int a =10;
static void int add(){
.
.
}
2) concluding
final modifier for finalizing of classes, methods in addition to variables.
Ex:
final int a =100;
.
.
.
a=200; //Error
---------------
int a =100;
.
.
.
.
a =200;
------------------
3) abstract
abstract modifier is to practice abstract classes, abstract methods
ex:
abstract course of teaching Sample{
.
.
}
-------------------------------
ii) Java Variables
1) What is Variable?
A named retentiveness place to shop the temporary information within a program.
Two types of memories inwards Computer environment
a) Primary retentiveness (RAM)
b) Secondary retentiveness (HDD, DVD, USB movement etc...)
----------------------------
2) Declaration of Variables
Java supports Explicit annunciation of Variables.
Syntax in addition to Examples:
dataType variableName;
int a;
-------------
dataType variablename=value;
int b=20;
---------------
dataType variable1, Variable2, variable3;
int a, b, c;
-----------------
dataType variable1=value; variable2=value; varible3=value;
int a=10; b=20; c=30;
------------------------------------
3) Assign values to variables
a) Initialization
b) Reading
Ex:
int a=100; //Initialization
int a=10;
int b;
b=a; //Reading
---------------------------------
4) Variable Naming Restrictions
> Java variables are illustration sensitive,
> Java variable nurture should start amongst a missive of the alphabet or $ or _
Ex:
myvar(Correct)
MYVAR
$myvar
_myvar
myvar_1
--------------
1myvar(Incorrect)
*myvar
----------------
> Variable names should non check amongst Java keywords/Reserved words.
> Must live unique inwards the range of declaration.
> Variable names Must non overstep 255 characters.
-------------------------------------------
5) Types of Variables
Three types of variables inwards Java
a) Local variable(Local variable is declared inwards methods or blocks.)
b) Instance variable(Instance variables are declared inwards a course of teaching but exterior of a method or whatever block)
c) Class/Static variableA Variable that is declared equally static, It cannot live local.
----------------------------------
Example:
package xyza;
public course of teaching VariablesExample {
//a Variable is a Class/Static variable
static int a =100;
//mysalary variable is a Local variable.
public int salary(){
int mysalary =10000+2000+1500;
mysalary=mysalary + a;
furnish mysalary;
}
public static void original (String[]args){
//Instance variable
int b =200;
System.out.println(a);//100
System.out.println(b); //200
VariablesExample obj= novel VariablesExample();
System.out.println(obj.salary());
// i is a Local Variable
for (int i=1; i<=5; i++){
System.out.println(i);
System.out.println(a);
System.out.println(b);
}
}
}
----------------------------------
iii) Java Operators
Important Categories of Operators
a) Arithmetic Operators
b) Relational Operators
c) Assignment Operators
d) Logical Operators
-------------------------------
a) Arithmetic Operators
1) Addition + (for Addition, String concatenation)
2) Subtraction - (for Subtraction, Negation)
3) Multiplication *
4) Division /
5) Modules %
6) Increment ++
7) Decrement --
---------------------------
Example:
public course of teaching OperatorsExample {
world static void original (String [] args){
int a =10, b=5;
String c ="Selenium", d= "Testing";
System.out.println("Addition of a, b is: "+ (a+b));//Addition of a, b is: 15
System.out.println("Subtraction of a, b is: "+ (a-b));
System.out.println("Multiplication of a, b is: "+ (a*b));
System.out.println("Division of a, b is: "+ (a/b));
System.out.println("Modules of a, b is: "+ (a%b));
b=10;
a = ++b;
System.out.println(a);//11
b=10;
a = --b;
System.out.println(a);//9
}
}
---------------------------------------
b) Relational Operators
1) ==
2) !=
3) >
4) >=
5) <
6) <=
----------------------------------
Note: Relational Operators furnish Boolean / Logical result
Example:
public course of teaching OperatorsExample {
world static void original (String [] args){
int a =10, b=20;
System.out.println((a>b));//false
System.out.println((a>=b));//false
System.out.println((a==b));//false
System.out.println((a<b));//true
System.out.println((a<=b));//true
System.out.println((a!=b));//true
}
}
------------------------------------------------
d) Logical Operators
1) Logical Not Operator !
2) Logical And Operator &&
3) Logical Or Operators ||
Result Criteria
Not operator
--------------
Operand1 Operand2 Result
--------------------------------------
true true false
true false true
false true true
false false true
--------------------------------------
And operator
--------------
Operand1 Operand2 Result
--------------------------------------
true true true
true false false
false true false
false false false
--------------------------------------
Or Operator
Operand1 Operand2 Result
--------------------------------------
true true true
true false true
false true true
false false false
--------------------------------------
Example:
public course of teaching OperatorsExample {
world static void original (String [] args){
boolean a =true, b=false;
System.out.println(!(a && b));//true
System.out.println((a && b));//false
System.out.println((a || b));//true
}
}
--------------------------------------
public course of teaching OperatorsExample {
world static void original (String [] args){
int a =1000, b=500, c=7000;
if ((a>b) && (a>c)){
System.out.println("A is a Big Number");
}
else{
System.out.println("A is Not a Big Number");
}
}
}
--------------------------------------
c) Assignment Operators
1) Assignment Operator
=
a=10;
2) Add in addition to Assign +=
3) Subtract in addition to assign
4) Multiple in addition to assign
-------------------------------
Example:
public course of teaching OperatorsExample {
world static void original (String [] args){
int a =10;
System.out.println(a);//10
a+=10;
System.out.println(a);//20
a-=10;
System.out.println(a);//10
a*=10;
System.out.println(a);//100
}
}
-----------------------------------------------------------
Bitwise Operators
> Java defines several bitwise operators, which tin live applied to the integer types, Bitwise operator works
on bits in addition to performs bit-by-bit operation.
i) The bitwise & operator performs a bitwise AND operation.
ii) The bitwise ^ operator performs a bitwise exclusive OR operation.
iii) The bitwise | operator performs a bitwise XOR operation.