c# program

1. This C# Program Implements PhoneBook.Reads a file with names and phone numbers
and builds a phone book from it and Returns the phone number for a given name.
Here is source code to Implement PhoneBook.The C# program is successfully
compiled and executed with Microsoft Visual Studio. The program output is also
shown below.
/*
* C# Program to Implement PhoneBook
*/
using System;
using System.Collections;
using System.IO;
class PhoneBook
{
static void Main(string[] arg)
{
Hashtable tab = new Hashtable();
string fileName;
if
{
(arg.Length > 0) fileName = arg[0];
}
else
{
fileName = "phoneBook.txt";
}
StreamReader r = File.OpenText(fileName);
string line = r.ReadLine();
while (line != null)
{
int pos = line.IndexOf('=');
string name = line.Substring(0, pos).Trim();
long phone = Convert.ToInt64(line.Substring(pos + 1));
tab[name] = phone;
line = r.ReadLine();
}
r.Close();
for (; ; )
{
Console.Write("Name : ");
string name = Console.ReadLine().Trim();
if (name == "")
break;
object phone = tab[name];
if (phone == null)
Console.WriteLine("-- Not Found in Phone Book");
else
Console.WriteLine(phone);
}
}
}
Here is the output of the C# Program:
Name : Ram
9999945670
Name : Raj
-- Not Found in Phone Book