There are some unique features of C# that make itself stand out from the sheer amount of programming languages in the wild.

Support for

1. Property syntax
2. Partial classes and methods
3. Extension methods
4. Anonymous types
5. Language Integrated Query (LINQ)

are some of the prominent ones.

Property syntax

Property syntax allow classes to provide a flexible mechanism for getting, setting, or computing the value of a private field (Docs, 2017).

public class SaleItem
{
   public string Name { get; set; }
   public decimal Price { get; set; }
}

Partial classes and methods

Partial classes and methods allow a class’s members to be defined in multiple files (Docs, 2015) which provide the following benefits:

1. multiple programmers to work on the same class at the same time
2. provide a mechanism to extend a compiler generated code

// File1
public partial class Employee
{
    public void DoWork()
    {
    }

    // partial method
    partial void onNameChanged();
}

// File2
public partial class Employee
{
    public void GoToLunch()
    {
    }

    partial void onNameChanged()  
    {  
        // method body  
    }  
}

Extension methods

Extension method is a statically-defined method that also allows programmers to extend the functionality of a class that cannot be modified, such as the built-in types.

public static class StringExtension
{
    // extend the built in string type
    public static int WordCount(this string str)
    {
        return str.Split(new char[] {' ', '.','?'}, StringSplitOptions.RemoveEmptyEntries).Length;
    }
}

Anonymous types

Anonymous type provide a simpler way to encapsulate a set of read only property into a single object and it is not necessary to define a type first. The type name is generated by compiler (Docs, 2015).

var v = new { Amount = 108, Message = "Hello" };
Console.WriteLine(v.Amount + v.Message);

Language Integrated Query (LINQ)

Language Integrated Query (LINQ) provide a unified language for querying data from various data source including XML documents, SQL databases, ADO.NET datasets, .NET collections or any other format provided that a LINQ provider is available (Docs, 2015)

// Query syntax
var result = from student in students
                where student.Scores[0] > 90
                select student;

// Fluent syntax
var result = students.Where(student => student.Scores[0] > 90);

References

1. Docs, M. (2017, March 9). Properties (C# Programming Guide). Retrieved from https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/properties
2. Docs, M. (2015, July 19). Partial Classes and Methods (C# Programming Guide). Retrieved from https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/partial-classes-and-methods
3. Docs, M. (2015, July 19). Anonymous Types (C# Programming Guide). Retrieved from https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/anonymous-types
4. Docs, M. (2015, July 19). Introduction to LINQ Queries (C#). Retrieved from https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/linq/introduction-to-linq-queries