C#: ASCII Art

An activity to introduce C# in 45-60m. C# is an object-oriented programming language, often used to make desktop applications. This lesson covers console output and methods. The goal of the lesson is to build a simple piece of ASCII art using the C# console.

Setup

Follow the Setup guide to get ready to build an introductory program with repl.it!

Introduction to ASCII Art

ASCII Art is a graphic design technique that uses text characters to create images.

Examples

Check out some examples of ASCII Art here: imgur.com/a/u9Rjhov

Drawing a Bunny in C#

Start by placing this bunny in a text file:

 () ()
 (^ ^)
 (___)

Using the C# console, it is possible to create interesting text-based art (like bunnies) using Console.WriteLine. Right now, it should show some text containing a message, but it can show any text at all! A developer simply needs to write out each line of ASCII text in the proper order. Try to recreate the bunny in the C# console!

Remove the existing code from body of the Main method
Add a Console.WriteLine statement to draw the bunny's ears
Add another Console.WriteLine statement to draw the bunny's face
Add a third Console.WriteLine statement to draw the bunny's body
Add an empty Console.WriteLine statement to add some space under the bunny
Make sure each piece of text starts with a space
Click the "run" button to see the bunny appear in the console!

using System;

class MainClass {
  public static void Main (string[] args) {
    Console.WriteLine(" () () ");
    Console.WriteLine(" (^ ^) ");
    Console.WriteLine(" (___) ");
    Console.WriteLine();
  }
}

Setting the Console Colors

It is possible to change the colors of the C# console. There is a limited set of colors, but they can make the console a little bit more fun.

At the top of the body of the Main method, add the following code:

Console.BackgroundColor = ConsoleColor.Cyan;
Console.ForegroundColor = ConsoleColor.DarkBlue;
Console.Clear();

This will set the colors, and then clear the existing console so that the colors apply to everything. Make sure the capitalization is consistent!

Try out a few different colors to see what works.

Challenge: Drawing Multiple Bunnies

Instead of drawing one bunny, draw a few bunnies lined up vertically. Use Console.WriteLine() to put an empty line in between them. Try to make all of the bunnies look the same!

Using Methods

The code starts to get a little more disorganized with each additional bunny. There is a lot of repeated code that does the exact same thing, and it becomes difficult to maintain. Luckily, methods can make this code better!

A method is a block of code that runs when it is called. This allows developers to reuse code; they can define the code once, and use it many times.

Questions

Q: Where is there already a method in the program? A: The Main method! This is the entry point for the exeuction of a C# program.

Q: For this program, what kind of method could help simplify the code? A: How about a method to draw a bunny!

Defining the Method

Under the Main method (after the }), start defining the method with public static void
- These keywords set certain things about the method. They are outside of the scope of this lesson
Add the name of the method: DrawBunny
Add parentheses and curly brackets (() {})
Click in between the opening and closing curly brackets and press the Enter key
In the body of the DrawBunny method, add the code to draw a bunny!

public static void DrawBunny() {
    Console.WriteLine(" () () ");
    Console.WriteLine(" (^ ^) ");
    Console.WriteLine(" (___) ");
    Console.WriteLine();
}

Calling the Method

Remove all of the bunny-drawing code from the body of the Main method
- Be sure to keep the console color code though!
Call the DrawBunny method in the code with DrawBunny();
Add a few additional method calls under the first one
Click the "run" button to run the code and see the bunnies appear!

Adding Whiskers

One of the best things about methods is that if a developer wants to update code, they only have to do it in one place. For example, to add whiskers to the bunny, it is only necessary to change one line of code instead of several. This change will apply to every method call!

In the DrawBunny method, find the line that draws the bunny's face
Add a greater-than sign (>) on the left side of the bunny's face
Add a less-than sign (<) on the right side of the bunny's face
Click the "run" button to run the code again and see each bunny appear with whiskers!

Challenge: An Additional Bunny Method

Define a new method under the existing method to draw the same bunny, but using an o for the eyes! The method definition should look almost exactly the same as the DrawBunny definition, but it should have a new name (DrawBunny2) and have o instead of ^ in the Console.WriteLine for the face.

Code

using System;

class MainClass {
    public static void Main (string[] args) {
        Console.BackgroundColor = ConsoleColor.Cyan;
        Console.ForegroundColor = ConsoleColor.DarkBlue;
        Console.Clear();

        DrawBunny();
        DrawBunny();
        DrawBunny();
    }

    public static void DrawBunny() {
        Console.WriteLine(" () () ");
        Console.WriteLine(">(^ ^)<");
        Console.WriteLine(" (___) ");
        Console.WriteLine();
    }
}

OPTIONAL: Method Parameters

The two methods, DrawBunny and DrawBunny2, are very similar. What are the differences?

The method names
The character used for the eyes

Instead of writing these two methods that are almost identical, it is possible to use method parameters to make the one method a little more dynamic. Method parameters allow developers to pass information to methods when they are called, so they can do different things depending on that information.

For this program, the eye is what will change with different method calls. The eye could be any piece of text at all, so the code in the body of the DrawBunnyEye method should not draw any eyes directly! Instead, it should insert the eye into the text dynamically.

Under the existing method definitions, define a new method named DrawBunnyEye
- Copy the existing definition for DrawBunny, but change the name
Add a parameter within the parentheses in the method definition: string eye
Update the code so that instead of using . for the eye, it uses whatever the user passed in (eye):
```
 Console.WriteLine($">({eye} {eye})<");
```
In the body of the Main method, call the DrawBunnyEye method, but put "^" inside the parentheses
Call the DrawBunnyEye method with a couple other eye values
Remove the other method definitions and calls, as they are no longer necessary
Click the "run" button to run the code again, and see the bunnies with all the different eyes!

Final Code

using System;

class MainClass {
    public static void Main (string[] args) {
        Console.BackgroundColor = ConsoleColor.Cyan;
        Console.ForegroundColor = ConsoleColor.DarkBlue;
        Console.Clear();

        DrawBunnyEye("^");
        DrawBunnyEye("$");
        DrawBunnyEye("0");
    }

    public static void DrawBunnyEye(string eye) {
        Console.WriteLine(" () () ");
        Console.WriteLine($">({eye} {eye})<");
        Console.WriteLine(" (___) ");
        Console.WriteLine();
    }
}

Next Steps

Try to create some different works of text-based art! Find some online by Google searching "ASCII Art" or make up your own! It can be helpful to start in Notepad before trying to write code.

NOTE: Using the backslash (\) character can cause issues when writing text to the screen. To avoid this, use \\ instead of \, and only one \ will appear.

ASCII Art