Notes

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections;
namespace ConsoleApp1
{
public class Class4
{
Hashtable h = new Hashtable();
//public Class4()
//{
// h = new Hashtable();
//}
public void add(dynamic key, dynamic value)
{
if (h.ContainsKey(key))
{
throw new Exception("key already present");
}
h.Add(key, value);
}
public string search(dynamic key)
{
if (!h.ContainsKey(key))
{
throw new Exception("key not present");
}
return h[key];
}
public void deleteit(dynamic key)
{
if (!h.ContainsKey(key))
{
throw new Exception("key not present to be deleted");
}
h.Remove(key);
}
public void print()
{
var key = h.Keys;
if (h.Count == 0)
{
Console.WriteLine("empty");
}
foreach (var item in key)
{
Console.WriteLine($"Mobile number : {item} nname : {h[item]}");
}
}
public void edit(dynamic key, dynamic value)
{
if (!h.ContainsKey(key))
{
throw new Exception("key not present");
}
else
{
h[key] = value;
}
}
}
}






private static Class4 c = new Class4();
static void Main(string[] args)
{
bool b = true;

while (b)
{
Console.WriteLine("1.addn2.Searchn3.deleten4.editn5.print all");
Console.WriteLine("Enter any option form [1-5]");
int ch = Convert.ToInt16(Console.ReadLine());
Console.Clear();
switch (ch)
{
case 1:
add();
break;
case 2:
search();
break;
case 3:
deleteit();
break;
case 4:
edit();
break;
case 5:
printall();
break;
default:
Invalid();
break;

}
Console.Clear();
Console.WriteLine("Enter "y" to continue");
var read1 = Console.ReadLine();
if (read1 != "y")
b = false;
Console.Clear();

}


}

private static void edit()
{
Console.WriteLine("Enter mobile number");
var mob = Console.ReadLine();
int flag = 0;
try
{
c.search(mob);
}
catch (Exception e)
{
Console.Clear();
Console.WriteLine(e.Message);
flag = 1;
}
if (flag == 0)
{
Console.WriteLine("Enter the new name associated with mobile number");
var name = Console.ReadLine();
Console.Clear();
try
{
c.edit(mob, name);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
flag = 1;
}
if (flag == 0)
{
Console.Clear();
Console.WriteLine("Modified sucessfully");
}
}
System.Threading.Thread.Sleep(2000);

}

private static void deleteit()
{
Console.WriteLine("Enter mobile number to search the record");
var mob1 = Console.ReadLine();
dynamic a = "";
int flag = 0;
try
{
c.deleteit(mob1);
}
catch (Exception e)
{
Console.Clear();
Console.WriteLine(e.Message);
flag = 1;
}
if (flag == 0)
{
Console.Clear();
Console.WriteLine("Deleted sucessfully");
}
System.Threading.Thread.Sleep(2000);
}

private static void Invalid()
{
Console.WriteLine("Enter valid options from 1 to 5.");
System.Threading.Thread.Sleep(2000);
}

private static void add()
{
Console.WriteLine("Enter mobile number");
var mob = Console.ReadLine();
Console.WriteLine("Enter name");
var name = Console.ReadLine();
Console.Clear();
int flag = 0;
try
{
c.add(mob, name);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
System.Threading.Thread.Sleep(2000);
flag = 1;
}
if (flag == 0)
{
Console.WriteLine("Added sucessfully");
}
System.Threading.Thread.Sleep(2000);
}
private static void search()
{
Console.WriteLine("Enter mobile number to search the record");
var mob1 = Console.ReadLine();
dynamic a = "";
int flag = 0;
try
{
a = c.search(mob1);
}
catch (Exception e)
{
Console.Clear();
Console.WriteLine(e.Message);
flag = 1;
}
if (flag == 0)
{
Console.Clear();
Console.WriteLine($"Name associated with the key {mob1} : {a}");
}
System.Threading.Thread.Sleep(2000);
}
private static void printall()
{
c.print();
System.Threading.Thread.Sleep(2000);
}