This document discusses different programming paradigms and compares procedural and object-oriented programming. It defines procedural programming as breaking a program into small subroutines or functions, while object-oriented programming breaks a program into objects that contain both data and code. Some key differences highlighted include objects having both data and methods while functions are separate, OOP following a bottom-up design and having features like inheritance and polymorphism. Examples of languages for each paradigm are provided.

2. Programming Paradigms :
Programming is a creative process carried out by programmers
to instruct a computer on how to do a task. A program is a set
of instructions that tells a computer what to do in order to
come up with a solution to a particular problem. There are a
number of alternative approaches to the programming
process, referred to as programming paradigms.
Different paradigms represent fundamentally different
approaches to building solutions to specific types of problems
using programming. Most programming languages fall under
one paradigm, but some languages have elements of multiple
paradigms. Two of the most important programming
paradigms are the procedural paradigm and the object-
oriented paradigm.

3. Procedural Programming
• Procedural Programming: It can be defined as a
programming model which is derived from structured
programming, based upon the concept of calling procedure.
Procedures, also known as routines, subroutines or functions,
simply consist of a series of computational steps to be carried
out. During a program’s execution, any given procedure
might be called at any point, including by other procedures or
itself.
• Languages used in Procedural Programming:
FORTRAN, ALGOL, COBOL, BASIC, Pascal and C.
*

4. Object Oriented Programming
• Object Oriented Programming: It can be defined as a
programming model which is based upon the concept of
objects. Objects contain data in the form of attributes and
code in the form of methods. In object oriented
programming, computer programs are designed using the
concept of objects that interact with real world. Object
oriented programming languages are class-based, meaning
that objects are instances of classes, which also determine
their types.
• Languages used in Object Oriented Programming:
Java, C++, C#, Python, PHP, JavaScript, Objective-C.
*

5. Procedural Programming Object-Oriented Programming
In procedural programming, the
program is divided into small parts
called functions.
In object-oriented programming, the
program is divided into small parts
called objects.
Procedural programming follows a top-
down approach.
Object-oriented programming follows
a bottom-up approach.
There is no access specifier in
procedural programming.
Object-oriented programming has
access specifiers like private, public,
protected, etc.
Adding new data and functions is not
easy.
Adding new data and function is easy.
Procedural programming does not
have any proper way of hiding data so
it is less secure.
Object-oriented programming
provides data hiding so it is more
secure.
In procedural programming,
overloading is not possible.
Overloading is possible in object-
oriented programming.
Difference Between Procedural and Object-Oriented Programming

6. In procedural programming, the function
is more important than the data.
In object-oriented programming, data is
more important than function.
Procedural programming is based on
the unreal world.
Object-oriented programming is based
on the real world.
In procedural programming, there is no
concept of data hiding and inheritance.
In object-oriented programming, the
concept of data hiding and inheritance is
used.
Procedural programming is used for
designing medium-sized programs.
Object-oriented programming is used
for designing large and complex
programs.
Procedural programming uses the
concept of procedure abstraction.
Object-oriented programming uses
the concept of data abstraction.
Code reusability absent in procedural
programming,
Code reusability present in object-
oriented programming.
Examples: C, FORTRAN, Pascal, Basic,
etc.
Examples: C++, Java, Python, C#, etc.

7. Modular Programming
Modular programming is the process of subdividing a
computer program into separate sub-programs. A module is a
separate software component. It can often be used in a
variety of applications and functions with other components
of the system.
• Some programs might have thousands or millions of lines
and to manage such programs it becomes quite difficult as
there might be too many of syntax errors or logical errors
present in the program, so to manage such type of
programs concept of modular programming approached.
• Each sub-module contains something necessary to execute
only one aspect of the desired functionality.
• Modular programming emphasis on breaking of large
programs into small problems to increase the
maintainability, readability of the code and to make the
program handy to make any changes in future or to correct
the errors.

8. Advantages of Using Modular Programming Approach –
Ease of Use :This approach allows simplicity, as rather than
focusing on the entire thousands and millions of lines code
in one go we can access it in the form of modules. This
allows ease in debugging the code and prone to less error.
Reusability :It allows the user to reuse the functionality
with a different interface without typing the whole
program again.
Ease of Maintenance : It helps in less collision at the time
of working on modules, helping a team to work with
proper collaboration while working on a large application.

9. Example:
// assumes all grades are for courses with same num of credits
double calculateGradeAverage(double[] grades) {
double sum = 0;
for (int i=0; i < grades.length; i++) // sum all grades
sum = sum + grades[i];
return (sum/grades.length); // calculate average
}
This program fragment is a Java method
called calculateGradeAverage that gets as input a list of grades, using an
array of data type double and returns the calculated average also as
double. In the method, we initialize the local variable sum to 0, and then
using a for-loop, we add all the grades to sum. Lastly, we divide the
obtained sum by the number of grades and return the value to the
caller of this method.
If our input array had the grades 3.5, 3.0, 4.0, after adding
them sum would have the value 10.5 and then it would be divided
by 3 since there are three grades. The method would return the
value 3.5.

10. Generics means parameterized types. The idea is to allow type
(Integer, String, … etc., and user-defined types) to be a
parameter to methods, classes, and interfaces. Using Generics, it
is possible to create classes that work with different data
types. An entity such as class, interface, or method that operates
on a parameterized type is a generic entity.
Generic Programming :

11. How Do Generics Work In Java?
Java Generics allow you to include a parameter in your
class/method definition which will have the value of a primitive
data type.
For Example: you can have a Generic class “Array” as follows:
Class Array<T> {….}
Where <T> is the parameterized type.
Next, you can create objects for this class as follows:
Array int_array<Integer> = new Array<Integer> ()
Array<Character> char_array = new Array<Character> ();
So given a Generic parameterized class, you can create
objects of the same class with different data types as
parameters. This is the main essence of using Java Generics.

12. Generic Classes
A Generic class is the same as a normal class except that the classname is
followed by a type in angular brackets.
A general definition of a Generic class is as follows:
class class_name<T>
{
class variables;
…..
class methods;
}
Once the class is defined, you can create objects of any data type that you want as follows:
class_name <T> obj = new class_name <T> ();
For Example, for Integer object the declaration will be:
class_name <Integer> obj = new class_name<Integer>;
Similarly, for the String data type, the object will be:
class_name <String> str_Obj = new class_name<String>;

13. Java Generics Method
Similar to the generics class, we can also create a method that can be used with any type of
data. Such a class is known as Generics Method.

14. class Main {
public static void main(String[] args) {
// initialize the class with Integer data
DemoClass demo = new DemoClass();
// generics method working with String
demo.<String>genericsMethod("Java Programming");
// generics method working with integer
demo.<Integer>genericsMethod(25);
}
}
class DemoClass {
// creae a generics method
public <T> void genericsMethod(T data) {
System.out.println("Generics Method:");
System.out.println("Data Passed: " + data);
}
}

15. Generics Method:
Data Passed: Java Programming
Generics Method: Data Passed: 25
OUTPUT:
public <T> void genericMethod(T data) {...}
Here, the type parameter <T> is inserted after the modifier public and before
the return type void.
We can call the generics method by placing the actual
type <String> and <Integer> inside the bracket before the method name.
demo.<String>genericMethod("Java Programming");
demo.<Integer>genericMethod(25);
In the above example, we have created a generic method
named genericsMethod.

16. OOP Concept
1)Class
2)Object
3)Data Abstraction
4)Encapsulation
5)Inheritance
6)polymorphism
7)Dynamic Binding
8)Message passing

17. Class
A class is a collection of instance variables and methods. instance
variables are the variables defined in the class and methods are the
functions defined in the class.
Syntax:
class classname
{
access_specifier type instance_variable=value;
access_specifier returntype methodname([type para1,…])
{
//body of method
}
…………
}

18. Example:
Class Studentdetails
{
public int roll_no;
protected String name;
void display()
{
System.out.println(name);
System.out.println(roll_no);
}
}

19. 1)Creation of class is no use if objects are not
constructed.Because class does not occupy
memory.To make use of a class ,object should be
created because objects are the actual variables
which occupy memory in ram.
2)Creation of classes is nothing but creation of
userdefined datatype.We can use this new
datatype(class) to create variables of the class
type

20. object
An object is an instantiation or implementation of
class. It contains variables and functions.
Syntax:
classname objectname=new classname();
classname objectname;//Here objectname is a
reference variable of classname.
The new operator allocates memory of classname()
dynamically which is said to be an object and
whose address is assigned to reference variable.
Example:
Studentdetails obj=new Studentdetails();

21. • Creation of classes is nothing but creation of
userdefined datatype.We can use this new
datatype(class) to create variables of the class
type .
• How ever creating objects of a class is a two step
process.
• First we must declare a reference variable of the
class.This reference variable does not define an
objects,instead it creates a variable that stores
reference(address) of an object.

22. Accessing class members
Syntax for accessing instance variable of a class:
objectname. instance variable ;
Ex:obj.name;
Syntax for accessing methods of a class:
objectname.method(arguments list……);
Ex:obj.display();

23. class Studentdetails
{
int roll_no=501;
String name="sai";
public void display()
{
System.out.println(name);
System.out.println(roll_no);
}
}
class Student
{
public static void main(String args[])
{
Studentdetails obj=new Studentdetails();
obj.display();
}
}
name
roll_no
display ()
obj
memory
1001
1001
Reference Variable
Object

24. Encapsulation
Binding (or wrapping) code and data together
into a single unit are known as encapsulation.
A java class is the example of encapsulation. Java
bean is the fully encapsulated class because all
the data members are private here.

26. Example
1)In pop, program is divided into
small parts called function .
1)In oop, program is divided into small
parts called object.

27. Abstraction:
Abstraction: Abstraction is a process where you show only “relevant” data
and “hide” unnecessary details of an object from the user
Hiding internal details and showing functionality is known as abstraction.
In Java, we use abstract class and interface to achieve abstraction.

28. Example:
abstract class sample
{
abstract void display(int a);
}
Class A extends sample
{
void display(int a)
{
x=a;
System.out.println(x);
}
}
class ex{
public static void main(string args[]);
A obj=new A();
obj.display(20);
}
}

29. DATA HIDING
Example:
class sample
{
private int x;
public void display(int a)
{
x=a;
System.out.println(x);
}
}
class ex
{public static void main(string args[]);
sample obj=new sample();
obj.display(20);
}
}

30. structure str
{
int roll_no;
char name[20];
};
C Structure C++ Structure
structure str
{
int roll_no;
char name[20];
member function();
};

31. Ex:int a=10;
Ex:int a[3];
a[0]=10;
a[1]=20;
a[2]=30;
structure str
{
char name[20];
int id;
};
str
name
id

32. Inheritance
Inheritance is a process in which one object acquires all the
properties and behaviors of its parent object automatically. In
such way, you can reuse, extend or modify the attributes and
behaviors which are defined in other class.
The class which inherits the members of another class is
called derived class and the class whose members are
inherited is called base class.

33. 1.Add money
2.Withdraw money
3.Take loan
4.Display Account Details
Bank in 90’s Bank in 20’s
1.Add money
2.Withdraw money
3.Take loan
4.Display Account Details
+
5.online money Transfer
6.Online pay cheques
7.Use of Debit/Credit cards
With out Inheritance
Class B
Class A

34. 1.Add money
2.Withdraw money
3.Take loan
4.Display Account Details
Bank in 90’s Bank in 20’s
1.Add money
2.Withdraw money
3.Take loan
4.Display Account Details
+
5.online money Transfer
6.Online pay cheques
7.Use of Debit/Credit cards
With out Inheritance
Class B
Class A

35. 1.Add money
2.Withdraw money
3.Take loan
4.Display Account Details
Bank in 90’s Bank in 20’s
1.Add money
2.Withdraw money
3.Take loan
4.Display Account Details
+
5.online money Transfer
6.Online pay cheques
7.Use of Debit/Credit cards
With Inheritance
Class B
Class A

36. 1.Add money
2.Withdraw money
3.Take loan
4.Display Account Details
Bank in 90’s Bank in 20’s
1.Add money
2.Withdraw money
3.Take loan
4.Display Account Details
+
5.online money Transfer
6.Online pay cheques
7.Use of Debit/Credit cards
With Inheritance
Class B
Class A

37. Example:
class A
{
int x=10;
}
class B extends A
{
System.out.println(x);
}
x=10

38. Polymorphism
When one task is performed by different ways i.e. known as
polymorphism.
In JAVA, we use Function overloading and Function overriding
to achieve polymorphism.
Example:
void area(int s)
{
System.out.println(s);
}
void area(int l,int b)
{
System.out.println(l*b);
}

39. It is the concept of binding of function call with the address of called function.
This binding can be of two types they are compile time binding and dynamic
binding.
class A
{
void sum(int x,int y)
{
System.out.println(x+y);
}
}
class B
{
public static void main(String args[])
{
A obj=new A();
obj.sum(2,4);
}
}
Dynamic binding

40. Objects communicate with
one another by sending and
receiving information.
A single object by itself may
not be very useful. An
application contains many
objects.
One object interacts with
another object by invoking
methods on that object.
It is also referred to
as Method Invocation.
Message passing

42. Documentation section
Package statement
Import Statement
Interface Statement
Class Definitions
Main method class
{
Main method definition
}
Structure/Creation of java Program

43. Documentation section:this section contains set of
comment line ,comment is used for giving the
name of the program and author & other details.
There are two types of comment
1)Single line comment(//)
2)multiline /**….
…..
….*/
Package statement:this statement declares
apackage name and informs the compiler that
classes defined here belonging to this package.
Import statement:this import statement is similar
to the #include statement in c.

44. • Interface statement:
• An interface is like a class but includes a group
of method declaration.
• Class definations :java program may have
number of classes of which only one class
defines a main method.
• Main method:every java program execution
starts from main method .this class is the
essential part of the java program.

45. HelloWorld program
// HelloWorld program
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
Class declaration:
A class declaration includes name and visibility of the class.
*
45 Java Programming Skills

46. HelloWorld program specification
• public: This is access modifier which is used to
define visibility. Here main method will be visible to
all other classes.
• static: static members belongs to class rather than any
specific object. It simply means you can access the
static members without object.
• void: void is another keyword which defines return
type of main method. It simply means main method
does not return anything before terminating the
program.
• main: main is method name here.
• String args[]: You can pass arguments to java program
using args[] array. It is used to take user input using
command line. *

47. Compilation & execution: command prompt
⚫ Compile
C:MyJava>javac HelloWorld.java
47
HelloWorld.java
javac
HelloWorld.class
compilation
Byte code
Source code
Platform specific
code
java
execution
Save the file as HelloWorld.java. A public class must be saved in the same name
as class name.
▪ Execute
C:MyJava>java HelloWorld
*
Java Programming Skills

48. Features/buzzwords of Java
⚫Simple
⚫Platform independent
⚫Portable
⚫High Performance
⚫Object-Oriented
⚫Multithreaded
⚫Secured
⚫Robust
⚫Distributed
⚫Compiler & Interpreted
⚫Architecture neutral
⚫Dynamic *

49. Features/buzzwords of Java
• Simple: Java is easy to learn. It does not include concepts
of pointers and operator overloading that were available in
C++.
• Platform independence: Java is write-once, run-
anywhere (WORA) language. Once you compile java
code, you can run it on any machine.
*

50. Features/buzzwords of Java
• Portable: Java bytecode can be portable to any platform
and can be executed on any platform.
• High performance: Java is interpreted language but it
has provided Just in time (JIT) compiler to increase
performance.
• Object Oriented: You can model everything into
an object which has data and behavior. Java has
incorporated various object-oriented concepts
such Abstraction, Encapsulation, Polymorphism,
and inheritance.
*

51. Features/buzzwords of Java
• Multi-threading: Java has provided multi-
threading feature which will help you to execute
various task in parallel. It does not occupy memory for
each thread. It shares a common memory area. Threads
are important for multi-media,window-based, and
Web-based applications, etc.
• Secured: Java is best known for its security. With Java,
we can develop virus-free systems. Java is secured
because: No explicit pointer and Java Programs run
inside a virtual machine sandbox. Java Runtime
Environment(JRE) which is used to load Java classes
into the Java Virtual Machine dynamically.
*

52. Features/buzzwords of Java
• Robust: (Robust means strong)
⮚ Java uses strong memory management.
⮚ There is a lack of pointers that avoids security
problems.
⮚ There is automatic garbage collection which runs on
the Java Virtual Machine to get rid of objects which
are not being used by a Java application anymore.
⮚ There are exception handling and the type checking
mechanism in Java.
All these points make Java robust.
*

53. Features/buzzwords of Java
⚫Distributed: Java facilitates users to create distributed
applications by using RMI and EJB. This feature of
Java makes us able to access files by calling the
methods from any machine on the internet.
⚫ Compile & Interpreted: Basically a computer
programming language is either compiled or interpreted.
But Java uses both compiler & interpreter. Initially java
compiler (javac) translates source code into byte code and
after that java interpreter (java) generates machine code
that can be directly executed.
*

54. Features/buzzwords of Java
⚫Architecture-neutral: Java is architecture neutral
because there are no implementation dependent
features, for example, the size of primitive types is
fixed. In C programming, int data type occupies 2
bytes of memory for 32-bit architecture and 4 bytes of
memory for 64-bit architecture. However, it occupies 4
bytes of memory for both 32 and 64-bit architectures
in Java.
⚫Dynamic: Java is a dynamic language. It supports
dynamic loading of classes. It means classes are loaded
on demand. It supports automatic memory
management (garbage collection).
*

55. Data types
⚫Data types refer to type of data that can be stored in
variable.
⚫As Java is strongly typed language, you need to define
data type of variable to use it and you can not assign
incompatible data type otherwise the compiler will
give you an error.
*

56. Data types
*

57. Primitive data types
Data Type Default Value Default size
boolean false 1 bit
char ‘u0000’ 2 byte
byte 0 1 byte
short 0 2 byte
int 0 4 byte
long 0L 8 byte
float 0.0f 4 byte
double 0.0d 8 byte
*

58. Reference data types
⚫Reference data types are those data types which are
provided as class by Java API or by class that you
create.
⚫String is an example of Reference data types provided
by java. String is an object of the class java.lang.String.
*

59. Variables
• These are used to store the values of elements while the
program is executed.
Types of variables
• Local variable
• A Variable which is declared inside a method can be termed
as Local Variable. It is mandatory to initialize local variable
otherwise Compiler will complain about it.
• Instance variable
• A Variable which is declared at class level can be termed
as Instance variable. It is not mandatory to initialize
Instance variable.
• All instance variable will be by default initialized by JVM.
• Static variable
• A Variable which is declared as static is known
as Static variable. Static variables are class level variables.
*

60. Variables:
Variables is an identifier used to store value.
Giving values to variables:
1)Assignment statement:-
Ex:int a=10;
2)Read statement:-
Ex:Scanner sc=new Scanner(System.in);
int a=sc.readInt();
1001 1002 1003 1004 1005
.
.
memory
1001
a
int a;

61. Read statement:- giving values to variable
interactively through the keyboard using the
scanner class methods .
Java User Input (Scanner)
The Scanner class is used to get user input, and it is
found in the java.util package.
To use the Scanner class, create an object of the
class and use any of the available methods found in
the Scanner class documentation. In our example,
we will use the nextLine() method, which is used to
read Strings:

62. nextBoolean() Reads a boolean value from the user
nextByte() Reads a byte value from the user
nextDouble() Reads a double value from the user
nextFloat() Reads a float value from the user
nextInt() Reads a int value from the user
nextLine() Reads a String value from the user
nextLong() Reads a long value from the user
nextShort() Reads a short value from the user
Input types
Method Description

63. //Write a program on scanner class
import java.util.Scanner;
class scanner
{
public static void main(String args[])
{
Scanner s1=new Scanner(System.in);
System.out.println(“Enter values=”);
int a=s1.nextInt();
int b=s1.nextInt();
int c=a+b;
System.out.println(“result=”+c);
}
}

64. Variable Demo Program
public class VariableDemo
{
int a; // Instance variable
static int b=20; // static variable
public void prints()
{
int c=10; // local variable
System.out.println("Method local variable: "+c);
}
public static void main(String args[])
{ //Instance and static variable
VariableDemo demo=new VariableDemo();
System.out.println("Instance variable: "+demo.a);
System.out.println("Static variable: "+b);
demo.prints();
}
} *

65. import java.util.Scanner;
class demo
{
public static void main(String[] args)
{
Scanner Obj = new Scanner(System.in);
System.out.println("Enter name, age and salary:");
String name = Obj.nextLine();
int age = Obj.nextInt();
double salary = Obj.nextDouble();
System.out.println("Name: " + name);
System.out.println("Age: " + age);
System.out.println("Salary: " + salary);
}
}

66. readLine() : method belongs to BufferedReader
class which is used to reads the input from the
keyboard as string which is then converted to
the corresponding datatype using wrapper
classes.
Ex:Integer.parseInt(),Float.parseFloat(),
Double.parseDouble(),Character.parseChar()

67. import java.io.*;
class Example
{
public static void main(String args[])throws Exception{
InputStreamReader r=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(r);
System.out.println("Enter your name");
String name=br.readLine();
System.out.println("Welcome "+name);
}
}

68. Arrays in JAVA
 Array is collection of related data items
 Creating an array
 Declare an array
 Create memory location
 Putting values to memory locations

69. Declaring an Array Variable
 Do not have to create an array while
declaring array variable
 <type> [ ] variable_name;
 Double[ ] myList;
 double myList[ ];
 Both syntaxes are equivalent
 No memory allocation at this point

70. Defining an Array
Define an array as follows:
 variable_name=new <type>[arraySize];
 Number = new int[5];
 Mylist = new int[10];
It creates an array using new dataType[arraySize];
 It assigns the reference of the newly created array to the variable
variable_name.
 dataType arrayname[ ] = {list of values};
 Int a [ ]={1,2,3,4,5,6,7,};
 Array index starts from 0 to arraySize-1;
 int is of 4 bytes, total space=4*10=40 bytes
Declaring and defining in the same statement:
 Double [ ] mylist = new double[10];


71. Creating arrays cntd...

72. What happens if we define different type…
 We define
 Int[ ] a=new long[20];
incompatible types
found: long[]
required: int[]
 The right hand side defines an array, and thus the array variable
should refer to the same type of array
Example:
int prime[100];
error=> ']' expected
long primes[20];
 The C++ style is not permitted in JAVA syntax
long[] primes = new long[20];
primes[25]=33;
Runtime Error:Exception in thread “main”
java.lang.ArrayIndexOutOfBoundsException

73. Array Size through Input
….
BufferedReader stdin = new BufferedReader (new
InputStreamReader(System.in));
String inData;
int num;
System.out.println("Enter a Size for Array:");
inData = stdin.readLine();
num = Integer.parseInt( inData ); // convert inData to int
long[] primes = new long[num];
System.out.println(“Array Length=”+primes.length);
….
SAMPLE RUN:
Enter a Size for Array:
4
Array Length=4

74. Example for array
public class TestArray {
public static void main(String[] args) {
double[] myList = {1.9, 2.9, 3.4, 3.5};
// Print all the array elements
for (double element: myList) {
System.out.println(element);
}
}
}
Otput:
1.9
2.9
3.4
3.5

75. Reusing Array Variables
 int[] primes=new int[10];
……
primes=new int[50];
 Previous array will be discarded
 Cannot alter the type of array

76. Demonstration
long[] primes = new long[20];
primes[0] = 2;
primes[1] = 3;
System.out.println(primes[0]);
System.out.println(primes[1]);
Output:
2
3

77. Array Length
 Refer to array length using length() method
 A data member of array object
 array_variable_name.length
 for(int k=0; k<primes.length;k++)
 Sample Code:
long[ ] primes = new long[20];
System.out.println(primes.length);
 Output: 20
 If number of elements in the array are
changed, JAVA will automatically change
the length attribute!

78. Sample Program
class MinArray
{
public static void main ( String[] args )
{
int[] array = { 20, 19, 1, 5, 71, 27, 19, 95 } ;
int min=array[0]; // initialize the current minimum
for ( int index=0; index < array.length; index++ )
if ( array[ index ] < min )
min = array[ index ] ;
System.out.println("The minimum of this array is:
" + min );
}
}

79. Two dimenssional array
 Representing 2D arrays
 Int myarray[][];
 Myarray = new int[3][4];
 Int myarray [][] = new int[3][4];
 Example
 Int myarray[2][3]={0,0,0,1,1,1};
2 columns and 3 rows

80. Operators in java
Operator in Java is a symbol which is used to perform
operations on operands.
There are many types of operators in Java which are given
below:
1)Arithmetic Operator
2)Relational Operator
3)Logical Operator
4)Assignment Operator.
5)Increment and decrement
6)Conditional
7)Bitwise Operator
8)Special operator

81. ArithmeticOperator: Arithmatic operators can be used to perform
simple mathematical calculations.
For example: +, -, *, / etc.
.
class OperatorExample
{
public static void main(String args[])
{
int a=10;
int b=5;
System.out.println(a+b);
System.out.println(a-b);
System.out.println(a*b);
System.out.println(a/b);
System.out.println(a%b);
}
}

82. Relational operators: Relational operators can be used to
compare two operands.
For Example: < , > , <= , >= , == , !=
class Relation
{
public static void main(String args[])
{
int a=10,b=5;
System.out.println(“a<b is“+(a<b));
System.out.println(“a>b is“+(a>b));
System.out.println(“a==b is”+(a==b));
System.out.println(“a<=b is”+(a<=b));
System.out.println(“a>=b is”+(a>=b));
System.out.println(“a!=b is “+(a!=b));
}
}

83. Logical operator: Logical operator can be used to combine two or
more conditions into one main condition.Based on this main condition
the If-Statement makes decision.
For Example: &&(And) , ||(OR) , !(Not)
Logical AND’ Operator(&&):
This operator returns true when both the conditions under
consideration are satisfied or are true. If even one of the two
yields false, the operator results false.
Logical OR' Operator(||):
This operator returns true when one of the two conditions under
consideration are satisfied or are true. If even one of the two
yields true, the operator results true.
Logical NOT' Operator(!): This is a unary operator returns true
when the condition under consideration is not satisfied or is a
false condition. Basically, if the condition is false, the operation
returns true and when the condition is true, the operation
returns false.

84. Logical AND’ Operator(&&):
class Logic
{
public static void main(String args[])
{
int age=25,experience=3;
if((age>22)&&(experience>2))
{
System.out.println(“eligible”);
}
else
{
System.out.println(“not eligible”);
}
}
}

85. class Logic
{
public static void main(String args[])
{
int age=25,experience=3;
if((age>22)||(experience>2))
{
System.out.println(“eligible”);
}
else
{
System.out.println(“not eligible”);
}
}
}
Logical OR' Operator(||):

86. Logical NOT' Operator(!)
class Logical {
public static void main(String[] args)
{
int a = 10, b = 1;
System.out.println("Var1 = " + a);
System.out.println("Var2 = " + b);
System.out.println("!(a < b) = " + !(a < b));
System.out.println("!(a > b) = " + !(a > b));
}
}
Output:
Var1 = 10
Var2 = 1
!(a < b) = true
!(a > b) = false

87. Assignment Operator: Assignment operator is one of the most
common operator. It is used to assign the value on its right to the
operand on its left.
For Example: =
class Operator
{
public static void main(String args[])
{
int a,b;
a=10;
b=20;
System.out.println(a);
System.out.println(b);
}
}

88. Increment and Decrement operator: Increment operator increments
the value of variable by one which it is operating.
For Example: ++
class Increment
{
public static void main(String args[])
{
int m=10, n=5;
System.out.println(“m=“+m);
System.out.println(“n=“+n);
System.out.println (“++m=“+(++m));
System.out.println(“m++=“+(m++));
System.out.println (“++n=“+(++n));
System.out.println(“n++=“+(n++));
System.out.println(“m=“+m);
System.out.println(“n=“+n);
}
}

89. Decrement operator: Decrement operator decrements the value
of variable by one which it is operating.
For Example: --
class Decrement
{
public static void main(String args[])
{
int m=10, n=5;
System.out.println(“m=“+m);
System.out.println(“n=“+n);
System.out.println (“--m=“+(--m));
System.out.println(“m--=“+(m--));
System.out.println (“--n=“+(--n));
System.out.println(“n--=“+(n--));
System.out.println(“m=“+m);
System.out.println(“n=“+n);
}
}

90. Conditional operator:Conditional operator will verifies the
condition if the condition is true then it will considers as the first
argument after the (?) and if the condition is false it considers the
second argument after(:) symbol.
Syntax: (condition)?argument1:argument2;

91. class Conditional
{
public static void main(String args[])
{
int a=10,b=20,x;
x=a<b?a:b;
System.out.println(“x=“+x);
}
}

92. Bitwise operator: Bitwise operators are used to perform the manipulation of
individual bits of a number.
It is used to test the bits,or shifting them to the right or left.
For Example: &, | , ~ ,^ ,<< , >>
class Bitwise
{
public static void main(String args[])
{
int a=60, b=13;
System.our.println(a&b);
System.our.println(a|b);
System.our.println(a^b);
System.out.println(~a);
System.out.println(a<<2);
System.out.println(a>>2);
}
}

93. Binary AND & Bitwise OR

94. Binary XOR & Once Complement

95. Binary Left Shift & Right Shift

96. Special operator:
Java support some special operator such as
1) Dot operator 2)instanceof operator
1)Dot operator:Dot operator is used to access the instance variables &
methods of class objects.
Ex:person.display();
2)instanceof operator:
The instanceof is an object reference operator
& returns true if the object on the lefthand side is an instanceof the
class given on the righthand side.
Ex:person instanceof student

97. Bitwise operator:It is used to test the bits,or shifting them to the right
or left.
For Example: << , >> , ~
class Bitwise
{
public static void main(String args[])
{
int a=60;
int b=13;
System.out.println(a<<2);
System.out.println(a>>2);
System.out.println(~a);
}
}

98. Special operator:
Java support some special operator such as
1) Dot operator 2)instanceof operator
1)Dot operator:Dot operator is used to access the instance variables &
methods of class objects.
Ex:person.display();
2)instanceof operator:
The instanceof is an object reference operator
& returns true if the object on the lefthand side is an instanceof the
class given on the righthand side.
Ex:person instanceof student

99. class student
{
int age=30;
void display()
{
System.out.println(age);
}
}
class detail
{
public static void main(String args[])
{
student person=new student();
person.display();
}
}

100. Program on instanceof operator
class test
{
public static void main(String args[])
{
String name=“james”;
boolean result=name instanceof String;
System.out.println(result);
}
}

101. TWO OBJECTS
class box
{
int w,h,d;
public int volume()
{
return w*h*d;
}}
class demo
{
public static void main(String args[])
{
box obj1=new box();
box obj2=new box();
obj1.w=1;
obj1.h=2;
obj1.d=3;
obj2.w=4;
obj2.h=5;
obj2.d=6;
int vol=obj1.volume();
System.out.println("volume="+vol);
int vol=obj2.volume();
System.out.println("volume="+vol);
}}
w
h
d
volume ()
obj1
w
h
d
volume ()
obj2

102. Program that uses a parameterized method
class box
{
int w,h,d;
public int volume(int w,int h,int d)
{
int vol= w*h*d;
System.out.println("volume="+vol);
}
}
class demo
{
public static void main(String args[])
{
box obj1=new box();
box obj2=new box();
obj1.volume(1,2,3);
obj2.volume(5,6,7);
}
}

103. Conditional statements
Conditional statements are used to perform different actions based
on different conditions.
The following conditional statements are:
• if statement
• if-else statement
• if-else-if ladder
• nested if statement

104. 1)If statement:The Java if statement tests the condition. It executes
the if block if condition is true.
Syntax:
if(condition){
//code to be executed
}
Ex:
class stmt
{
public static void main(String args[])
{
int stdmarks=70;
if(stdmarks>=60)
{
System.out.println(“passed”);
}
} }

105. class IfExample {
public static void main(String[] args)
{
int age=20;
if(age>18)
{
System.out.print("Age is greater than 18");
}
}
}

106. 2) if-else Statement:
The Java if-else statement also tests the condition. It executes the if
block if condition is true otherwise else block is executed.
Syntax:
if(condition){
//code if condition is true
}else{
//code if condition is false
}

107. //To display result
class stmt
{
public static void main(String args[])
{
int stdmarks=60;
if(stdmarks>=50)
{
System.out.println(“passed”);
}
else
{
System.out.println(“fail”);
}
}
}

108. //It is a program of odd and even number.
class IfElseExample
{
public static void main(String[] args)
{
int number=13;
if(number%2==0)
{
System.out.println("even number");
}
Else
{
System.out.println("odd number");
}
}
}

109. 3)if-else-if ladder Statement:
The if-else-if ladder statement executes one condition from multiple
statements.
Syntax:
if(condition1){
//code to be executed if condition1 is true
}
else if(condition2){
//code to be executed if condition2 is true
}
else if(condition3){
//code to be executed if condition3 is true
}
...
else
{
//code to be executed if all the conditions are false
}

110. class stmt
{
public static void main(String args[])
{
int stdmarks=98;
if(stdmarks>=90)
System.out.println(“Grade A”);
elseif(stdmarks>=80)
System.out.println(“Grade B”);
elseif(stdmarks>=70)
System.out.println(“Grade C”);
elseif(stdmarks>=60)
System.out.println(“Grade D”);
else
System.out.println(“failed”);
}
}

111. Nested if statement:
The nested if statement represents the if block within
another if block. Here, the inner if block condition
executes only when outer if block condition is true.
Syntax:
if(condition)
{
//code to be executed
if(condition)
{
//code to be executed
}
}

112. //Java Program to demonstrate the use of Nested If Statement
class JavaNestedIfExample
{
public static void main(String[] args)
{
int age=20;
int weight=80;
if(age>=18)
{
if(weight>50)
{
System.out.println("You are eligible to donate blood");
}
}
}
}

113. Conditional loops
In programming languages, loops are used to
execute a set of instructions/functions repeatedly
when some conditions become true. There are
three types of loops in Java.
• for loop
• while loop
• do-while loop

115. 1) For Loop:
The Java for loop is used to iterate a part of the
program several times. If the number of iteration
is fixed, it is recommended to use for loop.

116. A simple for loop is the same as C/C++. We can initialize the variable,
check condition and increment/decrement value.
It consists of four parts:
Initialization: It is the initial condition which is executed once when the
loop starts. Here, we can initialize the variable, or we can use an already
initialized variable. It is an optional condition.
Condition: It is the second condition which is executed each time to test
the condition of the loop. It continues execution until the condition is
false. It must return boolean value either true or false. It is an optional
condition.
Statement: The statement of the loop is executed each time until the
second condition is false.
Increment/Decrement: It increments or decrements the variable value. It is
an optional condition.
Syntax:
for(initialization;condition;incr/decr)
{
//statement or code to be executed
}

117. class ForExample
{
public static void main(String[] args)
{
for(int i=1;i<=10;i++)
{
System.out.println(i);
}
}
}

118. Java Nested For Loop
If we have a for loop inside the another loop, it is known as nested for loop.
The inner loop executes completely whenever outer loop executes.
class NestedForExample
{
public static void main(String[] args)
{
for(int i=1;i<=2;i++)
{
for(int j=1;j<=2;j++)
{
System.out.println(i+" "+j);
}
}
}
}

119. • Output:
• 11
• 12
• 21
• 22

120. Java for-each Loop
The for-each loop is used to traverse array or collection in java. It is
easier to use than simple for loop because we don't need to increment
value and use subscript notation.
It works on elements basis not index. It returns element one by one in the
defined variable.
Syntax:
for(Type var:array)
{
//code to be executed
}
Example:
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
for (String i : cars)
{
System.out.println(i);
}
The example above can be read like this: for each String element
(called i - as in index) in cars, print out the value of i.

121. /Java For-each loop example which prints the
//elements of the array
public class ForEachExample
{
public static void main(String[] args)
{
//Declaring an array
int arr[]={12,23,44,56,78};
//Printing array using for-each loop
for(int i:arr){
System.out.println(i);
}
}
}

122. //Java program to demonstrate the use of infinite for loop which prints an
statement
public class ForExample
{
public static void main(String[] args)
{
//Using no condition in for loop
for(;;)
{
System.out.println("infinitive loop");
}
}
}
Output:
infinitive loop
infinitive loop
infinitive loop
infinitive loop
infinitive loop
ctrl+c

123. Java While Loop
The java while loop is used to iterate a part of
the program several times. If the number of
iteration is not fixed, it is recommended to use
while loop.
Syntax:
while(condition){
//code to be executed
}

124. public class WhileExample
{
public static void main(String[] args)
{
int i=1;
while(i<=10){
System.out.println(i);
i++;
}
}
}

125. Java Infinitive While Loop
If you pass true in the while loop, it will be infinitive while loop.
Syntax:
while(true){
//code to be executed
}
Example:
public class WhileExample2 {
public static void main(String[] args) {
while(true){
System.out.println("infinitive while loop");
}
}
}
Output:
infinitive while loop
infinitive while loop
infinitive while loop
infinitive while loop
infinitive while loop
ctrl+c

126. Java do-while Loop
The Java do-while loop is used to iterate a part of the program
several times. If the number of iteration is not fixed and you
must have to execute the loop at least once, it is recommended
to use do-while loop.
The Java do-while loop is executed at least once because
condition is checked after loop body.
Syntax:
do{
//code to be executed
}while(condition);

127. public class DoWhileExample
{
public static void main(String[] args)
{
int i=1;
do{
System.out.println(i);
i++;
}while(i<=10);
}
}

128. Java Infinitive do-while Loop
If you pass true in the do-while loop, it will be infinitive do-
while loop.
Syntax:
do{
//code to be executed
}while(true);
Example:
public class DoWhileExample2 {
public static void main(String[] args) {
do{
System.out.println("infinitive do while loop");
}while(true);
}
}

129. Java Switch Statement
The Java switch statement executes one statement from multiple conditions. It
is like if-else-if ladder statement. The switch statement works with byte,
short, int, long, enum types, String and some wrapper types like Byte,
Short, Int, and Long. Since Java 7, you can use strings in the switch
statement.
In other words, the switch statement tests the equality of a variable against
multiple values.
Points to Remember
There can be one or N number of case values for a switch expression.
The case value must be of switch expression type only. The case value must
be literal or constant. It doesn't allow variables.
The case values must be unique. In case of duplicate value, it renders compile-
time error.
The Java switch expression must be of byte, short, int, long (with its Wrapper
type), enums and string.
Each case statement can have a break statement which is optional. When
control reaches to the break statement, it jumps the control after the switch
expression. If a break statement is not found, it executes the next case.
The case value can have a default label which is optional.

130. Syntax:
switch(expression)
{
case value1:
//code to be executed;
break; //optional
case value2:
//code to be executed;
break; //optional
......
default:
code to be executed if all cases are not matched;
}

131. class SwitchExample
{
public static void main(String[] args)
{
//Declaring a variable for switch expression
int number=20;
//Switch expression
switch(number){
//Case statements
case 10: System.out.println("10");
break;
case 20: System.out.println("20");
break;
case 30: System.out.println("30");
break;
//Default case statement
default:System.out.println(“Not in 10, 20 or 30 ");
}
}
}

132. class SwitchExample
{
public static void main(String[] args)
{ int i;
for(i=1;i<=4;i++)
{
switch(i)
{
Case 1:c=a+b;
System.out.println(c);
break;
Case 2:c=a-b;
System.out.println(c);
break;
Case 3:c=a*b;
System.out.println(c);
break;
Case 4:c=a/b;
System.out.println(c);
break;
default:System.out.println(" no operation ");
}
}
}

133. Break and continue:
• The Java break statement is used to break loop
or switch statement. It breaks the current flow of
the program at specified condition. In case of
inner loop, it breaks only inner loop.
• We can use Java break statement in all types of
loops such as for loop, while loop and do-while
loop.
• The continue statement breaks one iteration (in
the loop), if a specified condition occurs, and
continues with the next iteration in the loop.

134. class MyClass
{
public static void main(String[] args)
{
for (int i = 0; i < 10; i++)
{
if (i == 4)
{
break;
}
System.out.println(i);
}
}
}

135. class MyClass
{
public static void main(String[] args)
{
for (int i = 0; i < 10; i++)
{
if (i == 4)
{
continue;
}
System.out.println(i);
}
}
}

136. Pyramid Example 1:
public class PyramidExample
{
public static void main(String[] args)
{
for(int i=1;i<=5;i++)
{
for(int j=1;j<=i;j++)
{
System.out.print("* ");
}
System.out.println();//new line
}
}
}

137. Pyramid Example 2:
public class PyramidExample2
{
public static void main(String[] args)
{
int term=6;
for(int i=1;i<=term;i++)
{
for(int j=term;j>=i;j--)
{
System.out.print("* ");
}
System.out.println();//new line
}
}
}

138. Java Labeled For Loop
We can have a name of each Java for loop. To do so, we use label
before the for loop. It is useful if we have nested for loop so that
we can break/continue specific for loop.
Usually, break and continue keywords breaks/continues the
innermost for loop only.
Syntax:
labelname:
for(initialization;condition;incr/decr)
{
//code to be executed
}

139. //A Java program to demonstrate the use of labeled for loop
public class LabeledForExample {
public static void main(String[] args) {
//Using Label for outer and for loop
aa:
for(int i=1;i<=3;i++){
bb:
for(int j=1;j<=3;j++){
if(i==2&&j==2){
break aa;
}
System.out.println(i+" "+j);
}
}
}
}

140. Output:
1 1
1 2
1 3
2 1
If you use break bb;, it will break inner loop
only which is the default behavior of any loop.

141. public class LabeledForExample2 {
public static void main(String[] args) {
aa:
for(int i=1;i<=3;i++){
bb:
for(int j=1;j<=3;j++){
if(i==2&&j==2){
break bb;
}
System.out.println(i+" "+j);
}
}
}
}

142. Output:
1 1
1 2
1 3
2 1
3 1
3 2
3 3

143. Type conversion or Type casting
• Conversion from one data type value to
another data type value is known as type
conversion.
• Java supports type conversion in two ways.
1)Implicit conversion 2)Explicit conversion
• Implicit convertion:converting from one
datatype value to another datatype value
internally is called implicit convertion.
• It convert provided the following two
condition are satisfied

144. • Destination and source variable type should
be type compatible(i.e the datatypes of
variables should belong to same datatype
category)
• The destination variable data type size is
larger than source variable datatype.

145. Implicit conversion
Ex:
int x;
short y=20;
x=y;//correct
Ex:
int x=30;
short y;
y=x;//error
Type size
byte 1 byte
short 2 byte
int 4 byte
long 8 byte

146. Program on Implicit conversion
public class Conversion{
public static void main(String[] args)
{
int i = 200;
//automatic type conversion
long l = i;
//automatic type conversion
float f = l;
System.out.println("Int value "+i);
System.out.println("Long value "+l);
System.out.println("Float value "+f);
}
}
Int value 200
Long value 200
Float value 200.0
Output

147. Explicit convertion:
converting the source datatype value to the
destination datatype explicitly is known as
explicit type convertion
Ex:
int x=300;
byte y;
y=(byte)x;
Ex:
int x;
float y=95.67;
x=(int)y;

148. Explicit conversion
class Narrowing
{
public static void main(String[] args)
{
double d = 200.06;
long l = (long)d; //explicit type casting
int i = (int)l; //explicit type casting
System.out.println("Double Data type value "+d);
System.out.println("Long Data type value "+l); //fractional part lost
System.out.println("Int Data type value "+i); //fractional part lost
}
}
Double Data type value 200.06
Long Data type value 200
Int Data type value 200
output

149. Arrays in java
• Arrays are used to store multiple values in a single variable,
instead of declaring separate variables for each value.
• The elements of an array are stored in a contiguous memory
location. It is a data structure where we store similar elements.
• To declare an array, define the variable type with square
brackets:
• Note: Array indexes start with 0: [0] is the first element. [1] is
the second element, etc.

151. Types of Array in java
There are two types of array.
• Single Dimensional Array
• Multidimensional Array

152. • Single Dimensional Array
A list of items can be given one variable name using only one
subscript & such a variable is called one dimensional array.
Syntax to Declare an Array in Java
datatype arrayname[];
Ex: int n[];
Instantiation of an Array in Java
array_name =new datatype[size];
Ex: n=new int[5];
arrayname[subscript]=value;
Ex:n[0]=35;

153. class Testarray
{
public static void main(String args[])
{
int a[]=new int[5]; //declaration and instantiation
a[0]=10; //initialization
a[1]=20;
a[2]=70;
a[3]=40;
a[4]=50;
//traversing array
for(int i=0;i<a.length;i++)//length is the property of array
System.out.println(a[i]);
}
}
10 20 70 40 50
0 1 2 3 4

154. Multidimensional Array in Java
In such case, data is stored in row and column based index (also known as matrix
form).
Two dimensional arrays are similar to single dimensional arrays,the only difference
is a two dimensional array has two dimensions.
Syntax to Declare Multidimensional Array in Java
arrayname=new datatype[no. Of Elements] [no. Of Elements]
(OR)
datatype arrayname[][]={
{value1,values2…….},
{value3,values4……}
};
Example to instantiate Multidimensional Array in Java
a=new int[2][3];

155. Example of Multidimensional Java Array
class Testarray3
{
public static void main(String args[])
{
//declaring and initializing 2D array
int arr[][]={{10,20,30},{40,50,60}};
//printing 2D array
for(int i=0;i<2;i++)
{
for(int j=0;j<3;j++)
{
System.out.print(arr[i][j]+“t ");
}
System.out.print(“n”);
}
}
}
10 20 30
40 50 60
Output:

156. For-each Loop for Java Array
We can also print the Java array using for-each loop. The Java for-each loop
prints the array elements one by one. It holds an array element in a variable,
then executes the body of the loop.
class Testarray1
{
public static void main(String args[]){
int arr[]={33,3,4,5};
//printing array using for-each loop
for(int i:arr)
System.out.println(i);
}
}
The syntax of the for-each loop is given below:
for(data_type variable:array){
//body of the loop
}

157. Passing Array to a Method in Java
We can pass the java array to method so that we can reuse the same
logic on any array.
class Testarray2
{
//creating a method which receives an array as a parameter
static void min(int arr[])
{
int min=arr[0];
for(int i=1;i<arr.length;i++)
if(min>arr[i])
min=arr[i];
System.out.println(min);
}
public static void main(String args[])
{
int a[]={33,3,4,5};// declaring and initializing an array
min(a);//passing array to method
}
}
3
output

158. Anonymous Array in Java
Java supports the feature of an anonymous array, so you don't need to declare the array
while passing an array to the method.
//Java Program to demonstrate the way of passing an anonymous array
//to method.
class TestAnonymousArray
{
//creating a method which receives an array as a parameter
static void printArray(int arr[])
{
for(int i=0;i<arr.length;i++)
System.out.println(arr[i]);
}
public static void main(String args[])
{
printArray(new int[]{10,22,44,66});//passing anonymous array to method
}
}

159. Output:
10
22
44
66

160. Returning Array from the Method
We can also return an array from the method in Java.
//Java Program to return an array from the method
class TestReturnArray
{
//creating method which returns an array
static int[] get()
{
return new int[]{10,30,50,90,60};
}
public static void main(String args[])
{
//calling method which returns an array
int arr[]=get();
//printing the values of an array
for(int i=0;i<arr.length;i++)
System.out.println(arr[i]);
}

161. Output:
10
30
50
90
60

162. Multidimensional Array in Java
In such case, data is stored in row and column based index (also known as matrix
form).
Two dimensional arrays are similar to single dimensional arrays,the only difference
is a two dimensional array has two dimensions.
Syntax to Declare Multidimensional Array in Java
arrayname=new datatype[no. Of Elements] [no. Of Elements]
(OR)
datatype arrayname[][]={
{value1,values2…….},
{value3,values4……}
};
Example to instantiate Multidimensional Array in Java
a=new int[2][3];

163. Example of Multidimensional Java Array
class Testarray3
{
public static void main(String args[])
{
//declaring and initializing 2D array
int arr[][]={{1,2,3},{2,4,5},{4,4,5}};
//printing 2D array
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
System.out.print(arr[i][j]+" ");
}
System.out.println();
}
}
}
1 2 3
2 4 5
4 4 5
Output:

164. Jagged Array :If we are creating odd number of columns in a 2D array, it is known as
a jagged array. In other words, it is an array of arrays with different number of columns
class Main
{
public static void main(String[] args)
{
int arr[][] = new int[2][]; // Declaring 2-D array with 2 rows
arr[0] = new int[3]; // First row has 3 columns
arr[1] = new int[2]; // Second row has 2 columns
int count = 0;
for (int i=0; i<arr.length; i++) // Initializing array
for(int j=0; j<arr[i].length; j++)
arr[i][j] = count++;
System.out.println("Contents of 2D Jagged Array");
for (int i=0; i<arr.length; i++) // Displaying the values of 2D Jagged array
{
for (int j=0; j<arr[i].length; j++)
System.out.print(arr[i][j] + " ");
System.out.println();
}
}
}
0 1 2
3 4
Output:

165. Addition of 2 Matrices in Java
class Testarray5
{
public static void main(String args[]){
//creating two matrices
int a[][]={{1,3,4},{3,4,5}};
int b[][]={{1,3,4},{3,4,5}};
/creating another matrix to store the sum of two matrics
int c[][]=new int[2][3];
//adding and printing addition of 2 matrices
for(int i=0;i<2;i++){
for(int j=0;j<3;j++){
c[i][j]=a[i][j]+b[i][j];
System.out.print(c[i][j]+" ");
}
System.out.println();//new line
} }}
Output:
2 6 8
6 8 10

166. //This a first java program
class sample
{
public static void main(String args[])
{
System.out.println(“welcome to java lab”);
}
}

167. //Write a java program to add two numbers.
class add
{
public static void main(String args[])
{
int a,b,c;
a=100;
b=200;
c=a+b;
System.out.println(“result=“+c);
}
}

168. //Write a java to print biggest of two numbers.
class big
{
public static void main(String args[])
{
int a,b;
a=100;
b=200;
if(a>b)
System.out.println(“biggest=“+a);
else
System.out.println(“biggest=“+b);
}
}

169. //Write a java to print 1 to 10 numbers.
class loop
{
public static void main(String args[])
{
int i;
for(i=1;i<=10;i++)
{
System.out.println(“number=“+i);
}
}
}

170. public static void main(String args[])
public: public keyword is an acess specifier which allows the
programmer to control the visibility of class members.
static: The keyword static allows main() to be called without
having to instantiate a particular instance of the class.
void: It tells the compiler that main() does not have return type.
main(): Every java program execution starts from main function.
String args[]: Declares a parameter named args which is an
array of instances of the class string.

171. //With static method.
class A
{
public static void show()
{
System.out.println(“welcome”);
}
}
class B
{
public static void main(String args[])
{
A.show();
}
}
With out static method
class A
{
public void show()
{
System.out.println(“welcome”);
}
}
class B
{
public static void main(String args[])
{
A obj=new A();
obj.show();
}
} gedit A.java
javac A.java
Java B

172. Returning a value
class box
{
int w,h,d;
public int volume()
{
return w*h*d;
}
}
class demo
{
public static void main(String args[])
{
box obj=new box();
obj.w=1;
obj.h=2;
obj.d=3;
int vol=obj.volume();
System.out.println("volume="+vol);
}
}

173. Example: Argument,parameter,signature
class sample
{
int x;
public void display(int a)
{
x=a;
System.out.println(x);
}
}
class ex
{
public static void main(String args[])
{
sample obj=new sample();
obj.display(20);
}
}

174. Command Line argument:
•It is also possible to pass values to main() method & it can be
passed from command line because main() method is known as
command line arguments(run time)
•Values passed from command line exist in the form of strings
therefore the argument in the
main() is Strings therefore the argument in the main() is defined
as an array of String type.

175. Program to concatenate two argument value.
class commandline
{
public static void main(String args[])
{
String c=args[0]+args[1];
System.out.println(“result=“+c);
}
}

176. //Program on command line argument.
class commandline
{
public static void main(String args[])
{
int a,b,c;
a=Integer.parseInt(args[0]);
b=Integer.parseInt(args[1]);
c=a+b;
System.out.println(“result=“+c);
}
}
100 200
0 1
args

177. System.out.print():
class System
{
public PrintStream out;
.
.
.
}
class PrintStream
{
.
public void print();
public void print(int);
public void print(double);
public void print(char);
public void print(boolean);
public void print(float);
public void println();
public void println(int);
public void println(char);
public void println(float);
public void println(boolean);
public void println(double);
public void println(java.lang.string);
public void println(java.lang.object);
.
}

178. Scope and lifetime of a variable:
Scope determines the life time and visibility of an Identifier.
Identifier such as the variable name ,function name can be used
only in certain areas of a a program.

179. class test
{
public static void main(String args[])
{
int x=10;
if(x==10)
{
int y=20;
System.out.println(“x=“+x);
System.out.println(“y=“+y);
x=y*2;
}
System.out.println(“x=“+x );
//System.out.println(“y=“+y);
}
}

180. Access specifier
The access specifier of a members specifies the scope of the
member where it can be accessed.
There are four types:
1)Default:
2)Public:
3)Private:
4)Protected
Syntax:
class classname
{
access_specifier type instance_variable=value;
……….
access_specifier returntype methodname([type para1,…])
{
//body of method
}
}

181. 2)Public:
Ex:
class A
{
public int x=10;
}
3)Private:
Ex:
class A
{
private int x=10;
}
4)Protected:
Ex:
class A
{
protected int x=10;
}
1)Default:
Ex:
class A
{
int x=10;
}

182. • Default:the default member can be accessed
inside and outside the class but in the same
package.
• Public :the acess level of public modifier can be
accessed within the class outside the class with
in the package,outside the package.
• Private:the members declared with the access
• Specifier private can be accessed only with in the
class.
• Protected:the member declared with the access
specifier protected can be accessed with in the
• Class as well as its subclass.

183. structure str
{
int roll_no;
char name[20];
};
C Structure C++ Structure
structure str
{
int roll_no;
char name[20];
member function();
};

184. Ex:int a=10;
Ex:int a[3];
a[0]=10;
a[1]=20;
a[2]=30;
structure str
{
char name[20];
int id;
};
str
name
id

185. class sample
{
public int a=10;
private int b=20;
protected int c=30;
int d=40;
public static void main(String args[])
{
sample obj=new sample();
System.out.println(obj.a);
System.out.println(obj.b);
System.out.println(obj.c);
System.out.println(obj.d);
}
}

186. Write a program by using public ,private,protected
class Sample
{
private int x=10;
public int y=20;
protected int z=30;
int p=40;
}
class ex1
{
public static void main(String args[])
{
Sample obj=new Sample();
//System.out.println(obj.x);
System.out.println(obj.y);
System.out.println(obj.z);
System.out.println(obj.p);
} }

187. class A
{
private int x=10;
public int y=20;
protected int z=30;
int p=40;
}
class B extends A
{
void display()
{
//System.out.println(x);
System.out.println(y);
System.out.println(z);
System.out.println(p);
} }
class C extends B
{
void show()
{
//System.out.println(x);
System.out.println(y);
//System.out.println(z);
System.out.println(p);
}
}
class example
{
public static void main(String args[])
{
C obj=new C();
B obj2=new B();
obj2.display();
obj.show();
}

189. Accessing private variable in class
• To access or work with private instance of
class we have to define public method in the
class.
• Ex:we create a class with one private variable
x and we would like to perform two
operations on this variable.
• 1)setting value to x
• 2)printing value of x

190. Accessing private variable in class
class sample
{
private int x;
public void set(int a)
{
x=a;
}
public void display()
{
System.out.println(“x=“+x);
}
}
class ex
{
public static void main(String args[])
{
sample obj=new sample();
obj.set(100);
obj.display();
}}