C# Programming Labs

Your Task: Create a Person class with properties, a constructor, and methods to demonstrate core OOP concepts.

Detailed Requirements:
1. Create a class with properties:
class Person { // Auto-implemented properties public string Name { get; set; } public int Age { get; set; } } Properties in C# combine getter/setter methods into a clean syntax. { get; set; } creates auto-implemented properties.

2. Add a constructor:
public Person(string name, int age) { Name = name; Age = age; } Constructors initialize objects when created with new. The name matches the class name and has no return type.

3. Add a method:
public void Introduce() { Console.WriteLine($"Hi, I'm {Name} and I'm {Age} years old."); } Methods define behavior. public makes it accessible from outside the class.

4. Create objects and call methods:
Person person1 = new Person("Alice", 25); person1.Introduce(); Person person2 = new Person("Bob", 30); Console.WriteLine($"{person2.Name} is {person2.Age}");

💡 Pro Tips:
• Use private set; to make properties read-only from outside
• Add validation in property setters for data integrity
• Use this keyword to reference current instance
• Consider using record for simple data classes (C# 9+)
• Override ToString() for custom string representation

Expected Output:
Hi, I'm Alice and I'm 25 years old. Hi, I'm Bob and I'm 30 years old. Bob is 30 years old.

Your Task: Implement proper exception handling using try-catch-finally blocks to handle potential errors gracefully.

Detailed Requirements:
1. Basic try-catch structure:
try { // Code that might throw an exception int result = 10 / 0; // This causes DivideByZeroException } catch (DivideByZeroException ex) { Console.WriteLine($"Error: {ex.Message}"); }

2. Handle multiple exception types:
try { string input = "abc"; int number = int.Parse(input); // FormatException } catch (FormatException ex) { Console.WriteLine("Invalid number format!"); } catch (Exception ex) // Catch-all for other exceptions { Console.WriteLine($"Unexpected error: {ex.Message}"); } Order matters! Catch specific exceptions before general ones.

3. Use finally block:
try { // Attempt operation } catch (Exception ex) { Console.WriteLine($"Error: {ex.Message}"); } finally { // Always executes (cleanup code) Console.WriteLine("Cleanup complete."); } finally runs whether an exception occurred or not - perfect for cleanup.

4. Parse user input safely with TryParse:
string input = "42"; if (int.TryParse(input, out int number)) { Console.WriteLine($"Parsed: {number}"); } else { Console.WriteLine("Invalid input"); } TryParse is often better than catching exceptions for parsing.

💡 Pro Tips:
• Never catch Exception without logging or re-throwing
• Use throw; (not throw ex;) to preserve stack trace
• Don't use exceptions for flow control
• Create custom exceptions for domain-specific errors
• when keyword filters exceptions: catch (Exception ex) when (ex.Message.Contains("specific"))

Expected Output:
Attempting division... Error: Cannot divide by zero! Attempting to parse 'abc'... Error: Invalid number format! Finally block executed. Using TryParse: Successfully parsed 42

Your Task: Work with List<T> collections and use LINQ (Language Integrated Query) to query and transform data.

Detailed Requirements:
1. Create and populate a List:
using System.Collections.Generic; List<int> numbers = new List<int>(); numbers.Add(5); numbers.Add(2); numbers.Add(8); // Or use collection initializer: List<int> numbers = new List<int> { 5, 2, 8, 1, 9, 3 };

2. List operations:
numbers.Add(10); // Add element numbers.Remove(2); // Remove first occurrence of 2 numbers.Insert(0, 100); // Insert at index 0 int count = numbers.Count; // Get count (not Length!) numbers.Sort(); // Sort in place numbers.Reverse(); // Reverse in place

3. LINQ queries (add using System.Linq):
using System.Linq; // Filter with Where var evens = numbers.Where(n => n % 2 == 0); // Transform with Select var doubled = numbers.Select(n => n * 2); // Aggregate functions int sum = numbers.Sum(); double avg = numbers.Average(); int max = numbers.Max(); int min = numbers.Min(); // Order var sorted = numbers.OrderBy(n => n); var descending = numbers.OrderByDescending(n => n); // First/Last int first = numbers.First(); int last = numbers.Last();

4. Chain LINQ methods:
// Get even numbers, double them, sort descending var result = numbers .Where(n => n % 2 == 0) .Select(n => n * 2) .OrderByDescending(n => n) .ToList();

💡 Pro Tips:
• LINQ uses deferred execution - query runs when iterated
• Use .ToList() or .ToArray() to execute immediately
• => is the lambda operator (arrow function)
• FirstOrDefault() returns default if empty (no exception)
• Use Any() to check if collection has elements matching condition

Expected Output:
Original: 5 2 8 1 9 3 Count: 6 Sum: 28 Average: 4.67 Max: 9 Even numbers: 2 8 Doubled: 10 4 16 2 18 6 Sorted: 1 2 3 5 8 9