using System;
namespace pract9
{
 class Program
 {
 static void Main(string[] args)
 {
 Console.WriteLine("Pawan \n");
 int num, fact = 1;
 Console.WriteLine("Enter an number: ");
 num = int.Parse(Console.ReadLine());
 for (int i = 1; i <= num; i++)
 {
 fact = fact * i;
 }
 Console.WriteLine(fact);
 Console.ReadKey();
}
 }
}
Pract10
using System;
namespace pract10
{
 class Program
 {
 static void Main(string[] args)
 {
 Console.WriteLine("pawan \n");
 int inr;
 Console.WriteLine("Enter an Dollar Rupees");
 inr = int.Parse(Console.ReadLine());
 double rupee = inr * 82.88;
 Console.WriteLine("Converting After Dollar to indian Rupee : " +
 rupee);
 Console.ReadKey();
 }
 }
}
Pract 11
using System;
namespace pract11
{
 class Program
 {
 static void Main(string[] args)
 {
 Console.WriteLine("Pawan ");
 int a, b, c;
 Console.WriteLine("Enter an 'a' no: ");
 a = int.Parse(Console.ReadLine());
 Console.WriteLine("Enter an 'b' no: ");
 b = int.Parse(Console.ReadLine());
 Console.WriteLine("Enter an 'c' no: ");
 c = int.Parse(Console.ReadLine());
 double d, x1, x2;
 d = b * b - 4 * a * c;
 if (d == 0)
 {
 x1 = -b / (2.0 * a);
 x2 = x1;
 Console.WriteLine("First root 1" + x1);
 Console.WriteLine("Second root 1" + x2);
 }
 else if (d > 0)
 {
 x1 = (-b + Math.Sqrt(d)) / (2 * a);
 x2 = (-b - Math.Sqrt(d)) / (2 * a);
 Console.WriteLine("First root " + x1);
 Console.WriteLine("Second root " + x2);
 }
 else
 {
 Console.WriteLine("The answer is imaginary");
 }
 Console.ReadKey();
 }
 }
}
Pract 12
 Console.WriteLine("Pawan \n");
 double fahrenheit;
 double celsius;
 Console.WriteLine("Enter an Celsius: \n");
 celsius = int.Parse(Console.ReadLine());
 Console.WriteLine("Celsius: " + celsius);
 fahrenheit = (celsius * 9) / 5 + 32;
 Console.WriteLine("Fahrenheit: " + fahrenheit);
 Console.ReadLine();
Pract13
using System;
namespace pract13
{
 public class MathOperations
 {
 public int Add(int a, int b)
 {
 return a + b;
 }
 public double Add(double a, double b)
 {
 return a + b;
 }
 public string Add(string a, string b)
 {
 return a + b;
 }
 }
 class Program
 {
 static void Main(string[] args)
 {
 MathOperations A = new MathOperations();
 int intSum = A.Add(6, 3);
 double doubleSum = A.Add(4.2, 2);
 string stringConcatenation = A.Add("Hello", "Pawan");
 Console.WriteLine($"Integer sum: {intSum}");
 Console.WriteLine($"Double sum: {doubleSum}");
 Console.WriteLine($"String concatenation: {stringConcatenation}");
 Console.ReadKey();
 }
 }
}
Pract 14
using System;
// Base class
public class Vehicle
{
 public void Start()
 {
 Console.WriteLine("The Pawan" +" vehicle is starting.");
 }
}
// Single Inheritance: Derived class inherits from a single base class
public class Car : Vehicle
{
 public void Drive()
 {
 Console.WriteLine("The car is driving.");
 }
}
// Multilevel Inheritance: Derived class inherits from a class which itself inherits from
a base class
public class ElectricCar : Car
{
 public void Charge()
 {
 Console.WriteLine("The electric car is charging.");
 }
}
// Hierarchical Inheritance: Multiple derived classes inherit from the same base class
public class Truck : Vehicle
{
 public void Haul()
 {
 Console.WriteLine("The truck is hauling.");
 }
}
// Multiple Inheritance using Interfaces
public interface IFlyable
{
 void Fly();
}
public interface ISubmersible
{
 void Submerge();
}
public class AmphibiousVehicle : Vehicle, IFlyable, ISubmersible
{
 public void Fly()
 {
 Console.WriteLine("The amphibious vehicle is flying.");
 }
 public void Submerge()
 {
 Console.WriteLine("The amphibious vehicle is submerging.");
 }
}
class Program
{
 static void Main(string[] args)
 {
 Car car = new Car();
 car.Start();
 car.Drive();
 ElectricCar electricCar = new ElectricCar();
 electricCar.Start();
 electricCar.Drive();
 electricCar.Charge();
 Truck truck = new Truck();
 truck.Start();
 truck.Haul();
 AmphibiousVehicle amphibiousVehicle = new AmphibiousVehicle();
 amphibiousVehicle.Start();
 amphibiousVehicle.Fly();
 amphibiousVehicle.Submerge();
 Console.ReadKey();
 }
}
Pract15
using System;
namespace pract15
{
 public class Student
 {
 public string Name { get; set; }
 public int Age { get; set; }
 public string Major { get; set; }
 // Default constructor
 public Student()
 {
 Name = "Unknown";
 Age = 0;
 Major = "Undeclared";
 }
 // Constructor with two parameters
 public Student(string name, int age)
 {
 Name = name;
 Age = age;
 Major = "Undeclared";
 }
 // Constructor with three parameters
 public Student(string name, int age, string major)
 {
 Name = name;
 Age = age;
 Major = major;
 }
 public void DisplayInfo()
 {
 Console.WriteLine($"Name: {Name}, Age: {Age}, Major: {Major}");
 }
 }
 class Program
 {
 static void Main(string[] args)
 {
 Student student1 = new Student("Pawan", 20, "BscIt");
 Student student2 = new Student("Akash", 20, "Mca");
 Student student3 = new Student("Ahin", 22, "Computer Science");
 Console.WriteLine("Student 1:");
 student1.DisplayInfo();
 Console.WriteLine("\nStudent 2:");
 student2.DisplayInfo();
 Console.WriteLine("\nStudent 3:");
 student3.DisplayInfo();
 Console.ReadKey();
 }
 }
}
Pract16
using System;
namespace pract16
{
 class Program
 {
 static void Main(string[] args)
 {
 try
 {
 Console.Write("Pawan\n");
 Console.Write("Enter a number: ");
 int num = Convert.ToInt32(Console.ReadLine());
 int result = 10 / num;
 Console.WriteLine($"Result: {result}");
 }
 catch (DivideByZeroException)
 {
 Console.WriteLine("Error: Cannot divide by zero.");
 }
 catch (FormatException)
 {
 Console.WriteLine("Error: Invalid input format.");
 }
 finally
 {
 Console.WriteLine("Execution completed.");
 }
 Console.ReadKey();
 }
 }
}
Pract17
using System;
namespace pract17
{
 // Define a delegate
 delegate void MessageHandler(string message);
 class Notifier
 {
 // Declare an event of the delegate type
 public event MessageHandler MessageSent;
 public void SendNotification(string message)
 {
 Console.WriteLine($"Sending notification: {message}");
 MessageSent?.Invoke(message);
 }
 }
 class Subscriber
 {
 public void OnMessageReceived(string message)
 {
 Console.WriteLine($"Received message: {message}");
 }
 }
 class Program
 {
 static void Main(string[] args)
 {
 Notifier notifier = new Notifier();
 Subscriber subscriber = new Subscriber();
 // Subscribe the subscriber's method to the event
 notifier.MessageSent += subscriber.OnMessageReceived;
 Console.WriteLine("Enter a notification message:");
 string message = Console.ReadLine();
 // Send the notification, which triggers the event
 notifier.SendNotification(message);
 Console.ReadKey();
 }
 }
}
Pract 18