Safe Type Casting with IS and AS Operator

 if(obj is Employee)

{
   // to check an object is a type of my custom class type:
} 

 int i = 44;
object iBoxed = i;
int? jNullable = 42;
if (iBoxed is int a && jNullable is int b)
{
    Console.WriteLine(a + b);  // output 86
}

 if (input is null)
{
    return;
}

 if (result is not null)
{
    Console.WriteLine(result.ToString());
}

 int[] empty = [];
int[] one = [1];
int[] odd = [1, 3, 5];
int[] even = [2, 4, 6];
int[] fib = [1, 1, 2, 3, 5];

Console.WriteLine(odd is [1, _, 2, ..]);   // false
Console.WriteLine(fib is [1, _, 2, ..]);   // true
Console.WriteLine(fib is [_, 1, 2, 3, ..]);     // true
Console.WriteLine(fib is [.., 1, 2, 3, _ ]);     // true
Console.WriteLine(even is [2, _, 6]);     // true

 int itype = item as int;

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace AsOperator
{
    public class Employee { }
    public class Student { }
    public class College : Student { }
    class Program
    {
        static void Main(string[] args)
        {
            Student s = new Student();
            Employee e = new Employee();
            College c = new College();
            System.Collections.ArrayList list = new System.Collections.ArrayList();
            list.Add("Dotnetricks As Scholarhat");
            list.Add("12345");
            list.Add(s);
            list.Add(e);
            list.Add(c);
            foreach (object item in list)
            {
                // Try to convert item as a string
                string stype = item as string;

                if (stype != null)
                    Console.WriteLine(item.ToString() + " converted successfully.");
                else
                    Console.WriteLine(item.ToString() + " conversion failed.");
            }
            Console.ReadLine();
        }
    }
} 

 Dotnetricks As Scholarhat converted successfully.
12345 converted successfully.
AsOperator.Student conversion failed.
AsOperator.Employee conversion failed.
AsOperator.College conversion failed.