Basic Program Structure

Part of the Fundamentals section of Coddy's C# journey — lesson 4 of 69.

In C#, code is organized into classes. For now, just know that a class is where you'll write your code - we'll explain more about classes later

The Main method is a crucial part of a C# program because it serves as the starting point of execution.

Here's a simple breakdown of a basic C# program:

public class Program { // Class declaration
	public static void Main(string[] args) { // Main method
		Console.WriteLine("Hello, Coddy!"); // Output statement
		// Write code inside Main
	}
}

You write your code inside the Main method. The indentation (spaces at the start of lines) is used to make the code easier to read — it shows which code belongs inside which block.

Note: You may also see using System; at the top of some programs. This line appears outside the class and imports built-in functionality — for example, it allows you to use Console.WriteLine. It is not part of the class itself.

Important note: In C#, each statement must end with a semicolon (;). The semicolon is mandatory and tells C# that you've reached the end of a statement. Forgetting to add a semicolon will result in a compilation error.

However, note that code blocks enclosed in curly braces {} (like class and method declarations) don't need semicolons.

Challenge

Beginner

Create a C# program with a class named Program that contains the Main method. Inside the Main method, write code to output the following text:

This is my first C# program!

Cheat sheet

In C#, code must be inside a class. The Main method is the entry point where program execution begins.

Basic C# program structure:

public class Program {
	public static void Main(string[] args) {
		Console.WriteLine("Hello, Coddy!");
		// Write code inside Main
	}
}

Each statement must end with a semicolon (;). Code blocks with curly braces {} don't need semicolons.

Try it yourself

using System;

public class Program {
    // Write your code here
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

C#Hello World!CommentsBasic Program Structure

4Operators Part 1

Arithmetic Operators Modulo Operator Increment/Decrement Post Increment/Decrement Arithmetic Shortcuts

7Basic IO

Basic Output String Interpolation Reading Input Parse Recap - Till 120 Recap - True or False

10Methods (Functions)

Declaring Methods Method Parameters Return Types Optional Parameters Recap - Validation Function Void Methods

13Iterating Over Collections

Using For Loop Foreach Loop Common Array Operations

2Variables Part 1

Numbers Char String Boolean Type Declaration

5Operators Part 2

Comparison Operators Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3

8Calculator App

Welcome Message Getting Numbers

Basic Operations

Formatted Output

11Arrays Basics

Declaring Arrays Accessing Elements Modifying Arrays Array Methods Recap - Product Array Edit Recap - Reversed Array

14Final Challenges

Number Pattern Pattern Finder Student Grade Calculator

3Variables Part 2

Var Constants Naming Conventions Recap - Initialize Variables Type Casting

6Decision Making

If Statement If - Else Switch Statement Ternary Operator Recap - If Else Nested If - Else

9Loops

For Loop While Loop Do While Loop Break Continue Nested Loop Infinite Loop Recap - Dynamic Input

12String Operations

String Methods Part 1 String Methods Part 2 String Formatting