Pb.java

import java.io.*;
import java.util.*;
class Pb {
public static void main(String args[])
	throws IOException
	{
		Properties ht = new Properties();
		BufferedReader br =
		new BufferedReader(new InputStreamReader(System.in));
		String name, number;
		FileInputStream fin = null;
		boolean changed = false;
		try {
		fin = new FileInputStream("phonebook.dat");
		} catch(FileNotFoundException e) {
	}
	try {
		if(fin != null) {
			ht.load(fin);
			fin.close();
		}
	} 
	catch(IOException e) {
	System.out.println("Error reading file.");
	}
	do {
		System.out.println("Enter new name"+" ('quit' to stop): ");
		name = br.readLine();
		if(name.equals("quit")) continue;
		System.out.println("Enter number: ");
		number = br.readLine();
		ht.put(name, number);
		changed = true;
		} while(!name.equals("quit"));
	if(changed)
	{
		FileOutputStream fout = new FileOutputStream("phonebook.dat");
		ht.store(fout, "Telephone Book");
		fout.close();
	}
	do {
		System.out.println("Enter name to find" +"('quit' to quit): ");
		name = br.readLine();
		if(name.equals("quit")) continue;
		number = (String) ht.get(name);
		System.out.println(number);
	} while(!name.equals("quit"));
}
}