تغيير البرنامج .... لعمل العمليات الحسابيه

ما هي التغييرات التي اقوم بها لجعل البرنامج يقوم بالعمليات الحسابيه +-* / بشرط نفس البرنامج يعني التغييرات تكون محدوده

وشكرا

import java.io.*;

import java.net.*;

class TCPClient {

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

{

String sentence;

String modifiedSentence;

BufferedReader inFromUser =

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

Socket clientSocket = new Socket("34", 6789);

DataOutputStream outToServer =

new DataOutputStream(clientSocket.getOutputStream());

BufferedReader inFromServer =

new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

sentence = inFromUser.readLine();

outToServer.writeBytes(sentence + '\n');

modifiedSentence = inFromServer.readLine();

System.out.println("FROM SERVER: " + modifiedSentence);

clientSocket.close();

}

}

import java.io.*;

import java.net.*;

class TCPServer {

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

{

String clientSentence;

String capitalizedSentence;

ServerSocket welcomeSocket = new ServerSocket(6789);

while(true)

{

Socket connectionSocket = welcomeSocket.accept();

BufferedReader inFromClient =

new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));

DataOutputStream outToClient =

new DataOutputStream(connectionSocket.getOutputStream());

clientSentence = inFromClient.readLine();

System.out.println("FROM CLIENT: " + clientSentence+'\n');

capitalizedSentence = clientSentence.toUpperCase() + '\n';

outToClient.writeBytes(capitalizedSentence);

}

}

}