Lesson 3 — Language Rules

C# Syntax

C# syntax combines Java-style strictness with modern ergonomic improvements like expression bodies, string interpolation, and pattern matching.

CSHARP — Expression bodies 
// Standard statement — ends with semicolon:
int age = 21;
Console.WriteLine($"Age: {age}");

// Expression-bodied method (no braces, no return keyword):
static int Square(int n) => n * n;

// Standard equivalent:
static int SquareLong(int n) { return n * n; }

Naming Conventions

IdentifierConventionExample
Classes, Methods, PropertiesPascalCaseCalculateTotal()
Local variables, parameterscamelCasetotalAmount
Private fields_camelCase_balance
ConstantsPascalCaseMaxRetries
InterfacesIPascalCaseIPrintable
CSHARP — Comments and strings 
// XML documentation comment — Visual Studio renders in IntelliSense:
/// <summary>Returns a formatted greeting.</summary>
/// <param name="name">The learner's full name.</param>
/// <returns>A greeting string.</returns>
public static string Greet(string name) => $"Sawubona, {name}!";

// Verbatim string — backslashes are literal:
string path = @"C:\Users\Thandi\Documents";

// Raw string literal (C# 11+):
string json = """
    { "name": "Thandi", "course": "C#" }
    """;

Practice Task

Your Turn

Write a MyProfile class: private _birthYear field, Name property (PascalCase), Age property calculated from the current year, and a PrintProfile() method using interpolation. Add XML doc comments on the class and method.

Common Mistakes

  • Using camelCase for method names — C# methods are PascalCase.
  • Not prefixing private fields with underscore — C# convention is _fieldName.
  • Forgetting semicolons on statements.
  • Mixing C# and Java conventions in the same codebase.

Professional Tip

When you join a C# team, check their style guide first. Many South African enterprise teams follow Microsoft's official C# coding conventions document.

Mini Quiz

What is the correct casing for a C# method name?