Adding Variables and Methods

Adding variables

                 To a variable in a class it must be defined inside the class. At once a variable is added to a class it becomes instance variable.

Example

                class Student

                {

                                int reg_no;

                                 int mark_1;

                                int mark_2;

Defining a Class

                A class is a user defined data type. It contains data and its related methods. The general form is

class classname {      Datatype field-1;       ……………………….      Datatype field-n;      Datatype methodname-1(parameter list)      {            Body of the method       }      ………………………..      Datatype methodname-n(parameter list)      {           Body of the method      } }

Classes and Objects

1.          Java is a pure object oriented language. 
2.          So java program contains only classes. 
3.          Each class has its own data items and functions. 
4.          The data items are called fields and the functions are called methods.
5.          A class is a user defined data type and it represents the template of the fields and its related methods. 
6.          Object is a variable of type class and is used to access the class.

Program for Hormonic series

Program
import java.io.*;
class HormonicSeries
{
    public static void main(String args[])
    {
        float s=0f;int n=0;
        try
        {

Finding class of the IP address

Client:

import java.io.*;

import java.net.*;

import java.util.*;

class Clientip

{

            public static void main(String args[])

            {

            try

            {

                        BufferedReader in=new BufferedReader(new InputStreamReader(System.in));

                        Socket clsct=new Socket("127.0.0.1",139);

                        DataInputStream din=new DataInputStream(clsct.getInputStream());

                        DataOutputStream dout=new DataOutputStream(clsct.getOutputStream());

RPC and RMI operation in java

Client

import java.io.*;

import java.net.*;

import java.util.*;

class Clientrpc

{

            public static void main(String args[])

            {

            try

            {

                        BufferedReader in=new BufferedReader(new InputStreamReader(System.in));

                        Socket clsct=new Socket("127.0.0.1",139);

                        DataInputStream din=new DataInputStream(clsct.getInputStream());

                        DataOutputStream dout=new DataOutputStream(clsct.getOutputStream());

Stop and Wait in Java

Client

import java.io.*;

import java.net.*;

import java.util.*;

class Clientstop

{              public static void main(String args[])

                {try{while(true)

                                {String str1=null;

                                BufferedReader in=new BufferedReader(new InputStreamReader(System.in));

                                Socket clsct=new Socket("127.0.0.1",139);

                                DataInputStream din=new DataInputStream(clsct.getInputStream());

                                DataOutputStream dout=new DataOutputStream(clsct.getOutputStream());

Bitstuffing in java

Client

import java.io.*;

import java.net.*;

import java.util.*;

class Clientbs

{              public static void main(String args[])

                {try{       BufferedReader in=new BufferedReader(new InputStreamReader(System.in));

                                Socket clsct=new Socket("127.0.0.1",139);

                                DataInputStream din=new DataInputStream(clsct.getInputStream());

                                DataOutputStream dout=new DataOutputStream(clsct.getOutputStream());

File operation between client and server

File

Client

import java.io.*;

import java.net.*;

import java.util.*;

class Clientfile

{              public static void main(String args[])

                {try{

                                BufferedReader in=new BufferedReader(new InputStreamReader(System.in));

                                Socket clsct=new Socket("127.0.0.1",139);

                                DataInputStream din=new DataInputStream(clsct.getInputStream());

                                DataOutputStream dout=new DataOutputStream(clsct.getOutputStream());

                                System.out.println("Enter the file name:");

Program for Hamming code & CRC in Java

HAMMING CODE :

CLIENT

import java.io.*;

import java.net.*;

import java.util.*;

import java.math.*;

class Clienthamming

{          public static void main(String args[])

            {

            try      

            {         

                        BufferedReader in=new BufferedReader(new InputStreamReader(System.in));

                        Socket clsct=new Socket("127.0.0.1",139);

                        DataInputStream din=new DataInputStream(clsct.getInputStream());

                        DataOutputStream dout=new DataOutputStream(clsct.getOutputStream());

                        int x,y,z;

                        System.out.println("Enter the no.of bits in data word:");

                        String strr=in.readLine();

                        x=Integer.parseInt(strr);

                        System.out.println("Enter the no.of redundant bits:");