import java.io.*;
import java.net.*;

public class P2_3_Client
{	
	static void process()
	{	try
		{	BufferedReader user_input = new BufferedReader(new InputStreamReader(System.in));
		
			// create a socket
			....

			// get input & output streams
			....
			....

			// read and print to screen a message from server
			System.out.println(....);
			
			boolean hit = false;
			int row = 0, column = 0;
			String from_keyboard;
			
			/* when an array of type String is allocated  
		       it's elements are automatically set to null
			*/
			String[][] grid = new String[4][4];
			drawGrid(grid);
			
			do
			{	System.out.print("Enter row: ");
         		from_keyboard = user_input.readLine();
         		row =  Integer.parseInt(from_keyboard);
				System.out.print("Enter column: ");
         		from_keyboard = user_input.readLine();
         		column =  Integer.parseInt(from_keyboard);
         		
				// send co-ordinates to server
				....
				....
				
				// get indication of hit or miss from server
				hit = ....
				if (hit)
				{	System.out.println("HIT!");
					grid[row][column] = "h";
				}
				else
				{	System.out.println("MISS");
					grid[row][column] = "m";
				}
				drawGrid(grid);
			} while(!hit);

			// close input stream
			....

			// close output stream
			....

			// close socket
			....
		}
		catch(SocketException e)
		{	e.printStackTrace();
			System.exit(1);
		}
		catch (UnknownHostException e)
		{	System.out.println(e);
			System.exit(1); 
		}
		
		catch (IOException e)
		{	System.out.println(e);
			System.exit(1); 
		}
	}	
		
	static void drawGrid(String[][] grid)
	{	for (int r = 0; r < 4; r++)
		{	System.out.println(" ----- ----- ----- ----- ");
			System.out.println("|     |     |     |     |");
			System.out.print("|");
			for (int c = 0; c < 4; c++)
			{	if (grid[r][c] == null) 
					System.out.print("     |");	
				else
					if (grid[r][c].equals("m"))
						System.out.print("  O  |");
					else
						if (grid[r][c].equals("h"))
							System.out.print("  X  |");						
			}
			System.out.println();
			System.out.println("|     |     |     |     |");
		} 
		
		System.out.println(" ----- ----- ----- -----");
		System.out.println(); System.out.println();
	}	  
		
	public static void main(String args[])
	{	P2_3_Client client = new P2_3_Client();
		process();
	}	
}

import java.io.*;
import java.net.*;

public class P2_3_Server
{	
	public P2_3_Server()
	{	try 
		{	ServerSocket ....
			System.out.println("P2_3_Server is up and waiting for a connection..."); 
			getClients(....); 
		} 
		catch (IOException e) 
		{	System.out.println(e);
    		System.exit(1);
		}
	}


	static void getClients(ServerSocket server_socket)
	{	try
		{	// accept a connection request
			....

			// connection request received and processed, get input & output streams
			....
			....
			

			// generate random choice for battleship position 
			int battleship_row = (int) (Math.random() * 4);
			int battleship_column = (int) (Math.random() * 4);  
			boolean hit = false;
			int user_row, user_column;

			// send acknowledgement of request service to client 
			....("Connection to " + (InetAddress.getLocalHost()).getHostName() + " is successful");
			
			while (!hit)
			{	....
				....
				if (.... == battleship_row && .... == battleship_column) 
					hit = true;
				....(hit);
			}

			// close input stream
			....

			// close output stream
			....

			// close client socket
			....
		}
		catch (IOException e)
		{	System.out.println(e);
			System.exit(1); 
		}

	}
	
	public static void main(String args[])
	{	P2_3_Server server = new P2_3_Server();
	}
}