Comments

Learn to write single-line (//) and multi-line (/* */) comments in C#.

Single-line comment

Comments are used to add notes to a program. The compiler ignores them; they produce no output at runtime.

In C# a single-line comment starts with // and runs to the end of the line:

// This is a comment
Console.WriteLine("Hello");

Comments explain code and give hints to other developers (or your future self).

Multi-line comment

For comments that span multiple lines you use /* */. The comment starts with /* and ends with */.

/* This comment
   spans multiple
   lines */
Console.WriteLine("OK");

Multi-line comments are ideal for longer explanations. You cannot nest them; one /* closes with one */.

Exercise Use both comment types

Add a // comment, a /* */ comment to the program and print Welcome! with Console.WriteLine.

Show example solution

Inside Main add //, /* */ comments and Console.WriteLine("Welcome!");.
Example solution:
using System;

class Program
{
    static void Main()
    {
        // Greeting message
        Console.WriteLine("Welcome!");
        /* Program finished */
    }
}

Test yourself

Comment marker

____ This is a comment

Show answer

// This is a comment

Which one is a multi-line comment?
- // Comment
- # Comment
- /* Comment */
- 
Show answer

/* Comment */ — Correct! /* */ is the multi-line comment marker in C#.
Match the comment types

//

Single-line comment
/* */

Multi-line comment
///

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