C# Tutorial 3.1: Basic Syntax and Data Types

a. Hello World Program

Let's begin by creating a simple "Hello World" program in C#. This classic example helps us understand the basic syntax and structure of a C# program.

1. Create a New Console Application:

If you haven't done so already, open Visual Studio and create a new console application following the steps mentioned in Tutorial 2.

2. Write the "Hello World" Code:

Open the Program.cs file in the code editor and replace the existing code with the following:

using System;

class Program

{

    static void Main()

    {

        // This is a single-line comment

        /*

        This is a

        multi-line comment

        */

        // Displaying "Hello, World!" on the console

        Console.WriteLine("Hello, World!");

    }

}

3. Understand the Code:

• using System;: This line is an example of a using directive. It allows you to use types from the System namespace without specifying the full namespace every time.

• class Program: This declares a class named Program. In C#, the Main method, where the program starts executing, is typically located in a class named Program.

• static void Main(): This is the entry point of the program. Main is a method (function) that serves as the starting point for program execution.

• Console.WriteLine("Hello, World!");: This line uses the Console class to write the string "Hello, World!" to the console. WriteLine adds a newline after the specified text.

4. Run the Program:

Press F5 or click the "Start Debugging" button to build and run your program. You should see the output in the console window: "Hello, World!"

5. Comments in C#:

• Single-line comments: Created using //. Anything after // on a line is a comment.

• Multi-line comments: Enclosed between /* and */. Everything between these markers is a comment.

6. Experiment:

• Try modifying the "Hello, World!" text.
• Add your comments to the code.
• Experiment with different Console class methods, like Console.Write or formatting options.

Congratulations! You've successfully created and run a basic C# program. In the next tutorials, we'll explore variables, data types, and control flow statements.