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Name: Kumbhani Sanket Div: A Roll - No: 3111 DCN (P) - Assignment-3

The document contains code for a client-server program that performs checksum calculation on data sent over a socket connection. The server code accepts a connection, receives data from the client, calculates the checksum by adding binary representations of the data in 4-bit blocks, and sends the result back. The client code sends sample data to the server after dividing it into 4-bit blocks, receives the checksum result, and confirms successful transmission.

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Nayanvardhan Thakur
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41 views24 pages

Name: Kumbhani Sanket Div: A Roll - No: 3111 DCN (P) - Assignment-3

The document contains code for a client-server program that performs checksum calculation on data sent over a socket connection. The server code accepts a connection, receives data from the client, calculates the checksum by adding binary representations of the data in 4-bit blocks, and sends the result back. The client code sends sample data to the server after dividing it into 4-bit blocks, receives the checksum result, and confirms successful transmission.

Uploaded by

Nayanvardhan Thakur
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Name : Kumbhani Sanket

Div : A
Roll_no : 3111
DCN[P]_Assignment-3

Program: 1

//Kumbhani Sanket - 3111


import java.io.*;
import java.net.*;
import java.util.Scanner;

class server_checksum
{
public static void main(String[] args) throws Exception
{
try
{
ServerSocket serversocket = new ServerSocket(6666);
System.out.println("server is listening on
localhost:6666");

Socket socket = serversocket.accept();


DataInputStream instream = new
DataInputStream(socket.getInputStream());
DataOutputStream ostream = new
DataOutputStream(socket.getOutputStream());

String rmsg = instream.readUTF();


System.out.println("\nReceive msg ="+rmsg);
int len = 4;
// System.out.println(len);
String result = "";

while(result.length()<len)
{
result="0"+result;
}

for(int i=0;i<rmsg.length();i+=len)
{
String temp = rmsg.substring(i,i+len);
result = binadd(result,temp);
// System.out.println("result = "+result);
}
result = ones(result);
System.out.println("final result = "+result);

int flag=0;
for(int i=0;i<result.length();i++)
{
if(result.charAt(i)!='0')
System.out.println("Error");
else
flag=1;
}
if(flag!=0)
System.out.println("Run Successfully.");

ostream.close();
instream.close();
socket.close();
serversocket.close();
}
catch(Exception e)
{
System.out.println(e);
}
}

public static String binadd(String a,String b)


{
String result = "";
String carry = "0";
for(int i=a.length()-1;i>=0;i--)
{

if(a.charAt(i)==b.charAt(i))
{
if(a.charAt(i)=='1')
{
if(carry == "0")
{
result = "0"+result;
carry="1";
}
else
{
result = "1"+result;
carry="1";
}
}
else
{
if(carry=="1")
{
result = "1"+result;
carry="0";
}
else
{
result = "0"+result;
carry="0";
}
}

}
else
{
if(carry=="1")
{
result = "0" + result;
carry="1";
}
else
{
result = "1"+ result;
carry="0";
}
}
}
if(carry == "1")
{
while(carry.length()<a.length())
carry="0"+carry;
// System.out.print("carry encounter = ");
result = binadd(carry,result);
}
return result;
}

public static String ones(String msg)


{
String ans = "";
for(int i=0;i<msg.length();i++)
{
if(msg.charAt(i)=='0')
{
ans = ans+"1";
}
else
{
ans = ans+"0";
}
}
return ans;
}
}

-----------------------------------------------------------------------------------------------

//Kumbhani Sanket - 3111


import java.io.*;
import java.net.*;
import java.util.Scanner;

class client_checksum
{
public static void main(String[] args) throws Exception
{
try
{
Socket socket = new Socket("localhost",6666);

DataOutputStream ostream = new


DataOutputStream(socket.getOutputStream());
DataInputStream instream = new
DataInputStream(socket.getInputStream());

Scanner sc = new Scanner(System.in);


System.out.print("Enter msg:");
String msg = sc.nextLine();
System.out.print("Enter length:");
// int len = sc.nextInt();
// ostream.writeInt(len);
int len = 4;

String result = new String();


while(result.length()<len)
{
result="0"+result;
}

while(msg.length()%len!=0)
{
msg="0"+msg;
}
for(int i=0;i<msg.length();i+=len)
{
String temp = msg.substring(i,i+len);
System.out.print(result+" + "+temp+" = ");
result=binadd(result,temp);
System.out.println(result);
// System.out.println("result = "+result);
}
System.out.println("result = "+result);
result = ones(result);
System.out.println("result complement = "+result);
System.out.println("\nAddition = msg = "+msg+" +
result = "+result);
String sendmsg = msg + result;

ostream.writeUTF(sendmsg);
ostream.flush();
System.out.println("sendmsg = "+sendmsg);

instream.close();
ostream.close();
socket.close();
}
catch(Exception e)
{
System.out.println(e);
}
}

public static String binadd(String a,String b)


{
String result = "";
String carry = "0";
for(int i=a.length()-1;i>=0;i--)
{

if(a.charAt(i)==b.charAt(i))
{
if(a.charAt(i)=='1')
{
if(carry == "0")
{
result = "0"+result;
carry="1";
}
else
{
result = "1"+result;
carry="1";
}
}
else
{
if(carry=="1")
{
result = "1"+result;
carry="0";
}
else
{
result = "0"+result;
carry="0";
}
}
}
else
{
if(carry=="1")
{
result = "0" + result;
carry="1";
}
else
{
result = "1"+ result;
carry="0";
}
}
}
if(carry == "1")
{
while(carry.length()<a.length())
carry="0"+carry;
// System.out.print("carry encounter = ");
result = binadd(carry,result);
}
return result;
}

public static String ones(String msg)


{
String ans = "";
for(int i=0;i<msg.length();i++)
{
if(msg.charAt(i)=='0')
{
ans = ans+"1";
}
else
{
ans = ans+"0";
}
}
return ans;
}
}

Output:

Program: 2
//Kumbhani Sanket-3111
import java.net.*;
import java.io.*;
import java.util.Scanner;

class receiver_crc
{
public static void main(String args[]) throws Exception
{
try{
DatagramSocket ds1 = new DatagramSocket(6363);
System.out.println("server listening on localhost:6363");
byte[] buf = new byte[500];
DatagramPacket dp1 = new DatagramPacket(buf,500);
ds1.receive(dp1);
ds1.close();

String data = new String(dp1.getData(),0,dp1.getLength());


System.out.println("Received msg = "+ data);
String key = "11";
String rem = div(data,key);
System.out.println("rem = "+rem);
int cnt=0;
for(int i=0;i<rem.length();i++)
{
if(rem.charAt(i)=='0')
cnt++;
}
if(cnt!=0)
System.out.println("No error -> Successful.");

// DatagramSocket ds2 = new DatagramSocket();


// Scanner s = new Scanner(System.in);
// System.out.println("server:");
// String msg1 = s.nextLine();
// InetAddress ip = InetAddress.getByName("localhost");
// DatagramPacket dp2 = new
DatagramPacket(msg1.getBytes(),msg1.length(),ip,6565);
// ds2.send(dp2);
}catch(Exception e)
{System.out.println(e);}
}

public static String xor(String a, String b)


{
String result = "";
for(int i=1;i<a.length();i++)
{
if(a.charAt(i) == b.charAt(i))
result = result + "0";
else
result = result + "1";
}
return result;
}

public static String div(String data, String key)


{
int len = key.length();
for(int i=0;i<len-1;i++)
{
data = data + "0";
}

String zero = "";


for(int i=0;i<len;i++)
{
zero = zero + "0";
}

String temp = data.substring(0,len);


while(len<data.length())
{
if(temp.charAt(0)=='1')
temp = xor(temp,key) + data.charAt(len);
else
temp = xor(temp,zero) + data.charAt(len);
len++;
}

if(temp.charAt(0)=='1')
temp = xor(temp,key);
else
temp = xor(temp,zero);

return temp;
}
}

-----------------------------------------------------------------------------------------------

//Kumbhani Sanket-3111
import java.net.*;
import java.io.*;
import java.util.Scanner;

class sender_crc
{
public static void main(String args[]) throws Exception
{
try{
DatagramSocket ds1 = new DatagramSocket();
Scanner sc = new Scanner(System.in);
System.out.print("Enter Data: ");
String data = sc.nextLine();
String key = "11";
String rem = div(data,key);
System.out.println("rem = "+rem);
String sendmsg = data + rem;
System.out.println("send_msg = "+sendmsg);

InetAddress ip = InetAddress.getByName("localhost");

DatagramPacket dp1 = new


DatagramPacket(sendmsg.getBytes(),sendmsg.length(),ip,6363);
ds1.send(dp1);

}catch(Exception e)
{System.out.println(e);}
}

public static String xor(String a, String b)


{
String result = "";
for(int i=1;i<a.length();i++)
{
if(a.charAt(i) == b.charAt(i))
result = result + "0";
else
result = result + "1";
}
return result;
}

public static String div(String data, String key)


{
int len = key.length();
for(int i=0;i<len-1;i++)
{
data = data + "0";
}

String zero = "";


for(int i=0;i<len;i++)
{
zero = zero + "0";
}

String temp = data.substring(0,len);


while(len<data.length())
{
if(temp.charAt(0)=='1')
temp = xor(temp,key) + data.charAt(len);
else
temp = xor(temp,zero) + data.charAt(len);
len++;
}

if(temp.charAt(0)=='1')
temp = xor(temp,key);
else
temp = xor(temp,zero);

return temp;
}
}
Output:

Program: 3
//Kumbhani Sanket-3111
import java.net.*;
import java.io.*;
import java.util.Scanner;
import java.lang.Math;
import java.util.Arrays;

class receiver_hamming
{
public static void main(String args[]) throws Exception
{
try{
DatagramSocket ds1 = new DatagramSocket(6363);
System.out.println("server listening on localhost:6363");
byte[] buf = new byte[500];
DatagramPacket dp1 = new DatagramPacket(buf,500);
ds1.receive(dp1);
ds1.close();

String data = new String(dp1.getData(),0,dp1.getLength());


System.out.println("Received msg = "+ data);
// int a = Integer.parseInt(data);
// System.out.println(a);
int totalbits = data.length();
int rbits = 3;
int databits = totalbits - rbits;
// System.out.println(totalbits);
int rhcode[] = new int[totalbits+1];

//storing data into array


for(int i=0;i<totalbits;i++)
{
rhcode[i] = data.charAt(i) - '0';
}
System.out.println("***** Received Code : *****");
for(int i=0;i<totalbits;i++)
{
System.out.print("rhcode["+i+"] : "+rhcode[i]+"\t");
}
System.out.println();

//create array to store errorbits


int errorindex[] = new int[rbits];

for(int i=1,x=0,e=0; i<=totalbits; i++)


{
if(Math.pow(2,x)==i)
{
int counter = 0;

for(int sindex=i; sindex<=totalbits; sindex=sindex+i+i)


{
for(int index=sindex,cinc=1; index<=totalbits &&
cinc<=i; index++,cinc++)
{
//System.out.println("p["+index+"] :
"+hcode[index]);
if(rhcode[index] == 1)
{
counter++;
}
}
}
if(counter % 2 != 0)
{
errorindex[e]=i;
e++;
}
x++;
}
}

//check if any error is there or not


int sum=0;
System.out.print("\n errorIndex array values:");
for(int i=0;i<rbits;i++)
{
System.out.print(" "+ errorindex[i]);
sum = sum + errorindex[i];
}

//if sum < 0 then no error else error


if(sum>0)
{
System.out.println("\n Error at index: "+ sum);
//correct error, flip the bit at error index (0 to 1) & (1 to 0)
if(rhcode[sum]==0)
rhcode[sum]=1;
else
rhcode[sum]=0;
}
else
{
System.out.println("\nNo error in hamming code.");
}

System.out.print("\n final received hamming code: ");


for(int i=totalbits; i>=1; i--)
{
System.out.print(rhcode[i]);
}
System.out.println();

//extarct data from hamming code


int rdata[] = new int[databits+1];
for(int i=1,x=1,d=0; i<=totalbits; i++)
{
if(Math.pow(2,x)==i)
{
x++;
}
else
{
rdata[d] = rhcode[i];
d++;
}
}

System.out.print("\n received Data: ");


for(int i = databits; i>=1; i--)
{
System.out.print(rdata[i]);
}
System.out.println();
}catch(Exception e)
{System.out.println(e);}
}

-----------------------------------------------------------------------------------------------

//Kumbhani Sanket-3111
import java.net.*;
import java.io.*;
import java.util.Scanner;
import java.lang.Math;

class sender_hamming
{
public static void main(String args[]) throws Exception
{
try{
DatagramSocket ds1 = new DatagramSocket();
Scanner sc = new Scanner(System.in);
System.out.print("Enter Length of data:");
int databits = sc.nextInt();

int rbits = 0;
System.out.println("\nCalculating rbits:");
while(Math.pow(2,rbits) < databits+rbits+1)
{
System.out.println("2^" + rbits + " < " +databits+" + "+rbits+" +
1");
rbits++;
}

int totalbits = databits + rbits;


System.out.println("\nData bits: "+databits);
System.out.println("Redundent Bits: "+rbits);
System.out.println("Total Bits: "+totalbits);

//create array and store the data


int data[] = new int[databits+1];

//data stored in reverse order


System.out.println("\nEnter data into array:");
for(int i=databits; i>=1; i--)
{
data[i] = sc.nextInt();
}
System.out.println();

//printing array
System.out.println("\n *****data array:*****");
for(int i=1;i<=databits; i++)
{
System.out.print("\tdata["+i+"] = "+data[i]);
}
System.out.println();

//create array & store hamming code


int hcode[] = new int[totalbits+1];

//set values in hamming code


for(int i=1, x=0, k=1; i<=totalbits; i++)
{
if(Math.pow(2, x) == i)
{
hcode[i] = 0;
x++;
}
else
{
hcode[i]=data[k];
k++;
}
}
//printing hcode array
System.out.println("\n *****hcode array:*****");
for(int i=1;i<=totalbits;i++)
{
System.out.print("\thcode["+i+"] = "+hcode[i]);
}
System.out.println();

//calculating value of rbits


for(int i=1,x=0; i<=totalbits;i++)
{
if(Math.pow(2,x)==i)
{
int counter = 0;
System.out.println("\nrbits index : "+i);

for(int sindex=i; sindex<=totalbits; sindex=sindex+i+i)


{
for(int index=sindex,cinc=1; index<=totalbits &&
cinc<=i; index++,cinc++)
{
System.out.print("\tp["+index+"] : "+hcode[index]);
if(hcode[index] == 1)
{
counter++;
}
}
}
if(counter % 2 != 0)
{
hcode[i]=1;
}
else
{
hcode[i]=0;
}
x++;
}
}

//print final hamming code


System.out.print("\n hamming code:\t");
String store = "";
for(int i=totalbits; i>=1; i--)
{
System.out.print(hcode[i]);
store += Integer.toString(hcode[i]);
}
System.out.println();

InetAddress ip = InetAddress.getByName("localhost");

DatagramPacket dp1 = new


DatagramPacket(store.getBytes(),store.length(),ip,6363);
ds1.send(dp1);

}catch(Exception e)
{System.out.println(e);}
}

Output:

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