Basics Of Java: 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:");

String str1=in.readLine();

y=Integer.parseInt(str1);

z=x+y;

double count[]=new double[100];

String ar[]=new String[100];

String arr[]=new String[100];

System.out.println("Enter the binary data:");

for(int j=1;j<=x;j++)

{

ar[j]=in.readLine();

}

int k=x;

int w=1;

for(int j=3;j<=z;j++)

{

int a1=(int)Math.pow(2,w);

System.out.println("power"+a1);

if(j!=a1)

{

arr[j]=ar[k];

k--;

if(arr[j].equals("1"))

{

count[j]=1;

}

else

count[j]=0;

}

else

count[j]=0;

if(j-1==a1)

w++;

System.out.println(arr[j]+" in position "+j);

}

for(int i=0;i<y;i++)

{ double d=0;

int a=(int)Math.pow(2,i);

switch(a)

{

case 1:

for(int b=2;b<=z;b++)

{

d+=count[b+1];

b++;

}

break;

case 2:

for(int b=2;b<=z;b++)

{

d+=count[b]+count[b+1];

b++;b++;b++;

}

break;

case 4:

for(int b=4;b<=z;b++)

{

d+=count[b]+count[b+1]+count[b+2]+count[b+3];

b++;b++;b++;b++;b++;b++;b++;

}

break;

case 8:

for(int b=8;b<=z;b++)

{

d+=count[b]+count[b+1]+count[b+2]+count[b+3]+count[b+4]+count[b+5]+count[b+6]+count[b+7];

b=(b*i)-1;

}

break;

}

d%=2;

if(d==0)

arr[a]="0";

else

arr[a]="1";

}

dout.writeBytes(strr+'\n'+str1+'\n');

for(int i=1;i<=z;i++)

{

dout.writeBytes(arr[i]+'\n');

}

String str=din.readLine();

System.out.println(str);

clsct.close();

}

catch (Exception e)

{ System.out.println(e); }

}

SERVER

import java.io.*;

import java.net.*;

import java.util.*;

import java.math.*;

class Serverhamming

{ public static void main(String args[])

{

try

{

ServerSocket obj=new ServerSocket(139);

Socket obj1=obj.accept();

while(true)

{

DataInputStream din=new DataInputStream(obj1.getInputStream());

DataOutputStream dout=new DataOutputStream(obj1.getOutputStream());

String str1="Data Received Correctly";

String str2="Error in this position";

double count[]=new double[100];

String arr[]=new String[100];

String s[]=new String[10];

String strr=din.readLine();

int x=Integer.parseInt(strr);

System.out.println("No.of bits in Data word: "+x);

String str11=din.readLine();

int y=Integer.parseInt(str11);

System.out.println("No.of Redundant bit: "+y);

int z=x+y;

System.out.println("No.of bits in code word:"+z);

for(int i=1;i<=z;i++)

{

arr[i]=din.readLine();

if(arr[i].equals("1"))

{

count[i]=1;

}

else

count[i]=0;

}

for(int i=1;i<=z;i++)

{ System.out.println(arr[i]+" in position "+1);}

for(int j=0;j<y;j++)

{

double d=0;

int a=(int)Math.pow(2,j);

switch(a)

{

case 1:

for(int b=1;b<=z;b++)

{

int s1=b%2;

if(s1!=0)

d+=count[b];

}

break;

case 2:

for(int b=2;b<=z;b++)

{

d+=count[b]+count[b+1];

b++;b++;b++;

}

break;

case 4:

for(int b=4;b<=z;b++)

{

d+=count[b]+count[b+1]+count[b+2]+count[b+3];

b++;b++;b++;b++;b++;b++;b++;

}

break;

case 8:

for(int b=8;b<=z;b++)

{

d+=count[b]+count[b+1]+count[b+2]+count[b+3]+count[b+4]+count[b+5]+count[b+6]+count[b+7];

b=(b*j)-1;

}

break;

}

d%=2;

if(d==0)

count[a]=0;

else

count[a]=1;

}

if(x<=4)s[y]="0";

for(int j=0;j<y;j++)

{

int a=(int)Math.pow(2,j);

if(count[a]==0)

{

s[j]="0";

}

else

s[j]="1";

}

if(s[0].equals("0") && s[1].equals("0") && s[2].equals("0") && s[3].equals("0"))

dout.writeBytes(str1+'\n');

else

dout.writeBytes(str2+" "+s[3]+s[2]+s[1]+s[0]+'\n');

obj.close();

}

catch(Exception e)

{ System.out.println(e);}

}

OUTPUT

Client

Enter the no.of bits in data word:

Enter the no.of redundant bits:

Enter the binary data:

power2

0 in position 3

power4

null in position 4

power4

1 in position 5

power8

0 in position 6

power8

0 in position 7

power8

null in position 8

power8

0 in position 9

power16

0 in position 10

power16

0 in position 11

Server

No.of bits in Data word: 7

No.of Redundant bit: 4

No.of bits in code word:11

1 in position 1

0 in position 1

1 in position 1

0 in position 1

Client

Data Received Correctly

CRC

Client

import java.io.*;

import java.net.*;

class crccli

{

public static void main(String args[]) throws Exception

{

byte b[]=new byte[1024];

DatagramSocket ds=new DatagramSocket(5000);

DatagramPacket dp=new DatagramPacket(b,1024);

String s;

StringBuffer s1=new StringBuffer(11);

int i,j=0;

int temp[]=new int[4];

int divisor[]=new int[4];

divisor[3]=1;

divisor[2]=1;

divisor[1]=0;

divisor[0]=1;

int dividend[]=new int[11];

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

System.out.println("Enter a character: ");

s=buf.readLine();

System.out.println("The ASCII value of the character is "+(int)s.charAt(0));

s=Integer.toBinaryString((int)s.charAt(0));

System.out.println("The Binary equivalent is "+s);

i=s.length()-1;

for(j=0;j<3;j++)

dividend[j]=0;

while(i>=0)

{

if((int)s.charAt(i)==48)

dividend[j]=0;

else

dividend[j]=1;

i--;

j++;

}

while(j<11)

{

dividend[j]=0;

j++;

}

System.out.print("The Dividend is ");

for(i=10;i>=0;i--)

System.out.print(dividend[i]);

System.out.println("\n");

System.out.print("The divisor is ");

for(i=3;i>=0;i--)

System.out.print(divisor[i]);

System.out.println("\n");

temp[3]=dividend[10];

temp[2]=dividend[9];

temp[1]=dividend[8];

for(i=10;(i-3)>=0;i--)

{

temp[0]=dividend[i-3];

if(temp[3]==0)

{

for(j=3;j>=0;j--)

temp[j]=temp[j]^0;

}

else

{

for(j=3;j>=0;j--)

temp[j]=temp[j]^divisor[j];

}

for(j=3;j>0;j--)

temp[j]=temp[j-1];

}

System.out.println("The remainder is "+temp[3]+temp[2]+temp[1]);

dividend[2]=temp[3];

dividend[1]=temp[2];

dividend[0]=temp[1];

for(i=0;i<11;i++)

{

if(dividend[i]==0)

s1.insert(i,"0");

else

s1.insert(i,"1");

}

s=s1.toString();

System.out.println("The data to be sent is "+s1.reverse());

b=s.getBytes();

ds.send(new DatagramPacket(b,b.length,InetAddress.getLocalHost(),5001));

ds.receive(dp);

String result=new String(dp.getData(),0,dp.getLength());

System.out.println(result);

}

Server

import java.io.*;

import java.net.*;

class crcser

{

public static void main(String args[]) throws Exception

{

byte b[]=new byte[1024];

DatagramSocket ds=new DatagramSocket(5001);

DatagramPacket dp=new DatagramPacket(b,1024);

String s=new String();

int i,j=0;

int temp[]=new int[4];

int divisor[]=new int[4];

divisor[3]=1;

divisor[2]=1;

divisor[1]=0;

divisor[0]=1;

int dividend[]=new int[11];

ds.receive(dp);

String s1=new String(dp.getData(),0,dp.getLength());

StringBuffer s2=new StringBuffer(s1);

System.out.println("Data received: "+s2.reverse());

for(i=0;i<11;i++)

{

if((int)s1.charAt(i)==48)

dividend[i]=0;

else

dividend[i]=1;

}

System.out.print("The divisor is ");

for(i=3;i>=0;i--)

System.out.print(divisor[i]);

System.out.println("\n");

temp[3]=dividend[10];

temp[2]=dividend[9];

temp[1]=dividend[8];

for(i=10;(i-3)>=0;i--)

{

temp[0]=dividend[i-3];

if(temp[3]==0)

{

for(j=3;j>=0;j--)

temp[j]=temp[j]^0;

}

else

{

for(j=3;j>=0;j--)

temp[j]=temp[j]^divisor[j];

}

for(j=3;j>0;j--)

temp[j]=temp[j-1];

}

System.out.println("The remainder is "+temp[3]+temp[2]+temp[1]);

if(temp[3]==0&&temp[2]==0&&temp[1]==0)

{

System.out.println("No errror in packet");

s="Packet received at server without error";

}

else

{

System.out.println("Errror in packet");

s="Packet received at server with error";

}

b=s.getBytes();

ds.send(new DatagramPacket(b,b.length,InetAddress.getLocalHost(),5000));

}

Output

Enter a character:

The ASCII value of the character is 48

The Binary equivalent is 110000

The Dividend is 00110000000

The divisor is 1101

The remainder is 011

The data to be sent is 00110000011

Server

Data received: 00110000011

The divisor is 1101

The remainder is 000

No errror in packet

Client

Packet received at server without error

Basics Of Java

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Tuesday 13 September 2011

Program for Hamming code & CRC in Java

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