C# Advanced Features - Complete Explanation

This code demonstrates several important C# features introduced in C# 3.0 and later versions. Let's explore each concept in detail.

1. Partial Classes

Theory

Partial classes allow you to split the definition of a class across multiple source files. This is particularly useful for:

• Large classes that multiple developers work on
• Code generation scenarios (like Windows Forms designer)
• Separating different aspects of a class (UI logic vs business logic)

Key Rules

• All parts must use the partial keyword
• All parts must be in the same namespace
• All parts must be in the same assembly
• Access modifiers must be consistent

Example Implementation

// File: MathsOperations.cs
public partial class Maths
{
    public int Add(int a, int b)
    {
        return a + b;
    }
}

// File: MathsAdvanced.cs
public partial class Maths
{
    public int Sub(int a, int b)
    {
        return a - b;
    }
}

2. Implicit Type Declaration (var keyword)

Theory

The var keyword enables implicit type declaration where the compiler infers the type from the right-hand side of the assignment. This feature provides:

• Cleaner code for complex types
• Better readability in LINQ expressions