Merge pull request #4 from jongalloway/unit-2-markdown-formatting

Markdown formatting fixes
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James Montemagno 2022-05-10 15:06:19 -07:00 committed by GitHub
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In this C# Crash Course, we'll go over the basics of C# so that you'll be ready to build out exciting web apps! We'll start by going through the key attributes of C#, syntax basics, and introduce you to OOP. In each section, we'll link you to some quick in-browser C# challenges so you can apply these concepts.
## Topics you'll learn
* Language attributes
* Syntax basics
* Object Oriented Programming
@ -10,22 +11,29 @@ In this C# Crash Course, we'll go over the basics of C# so that you'll be ready
---
# Language attributes
C# is a strongly typed, compiled, object oriented language. Let's break this down.
## Strongly typed
In a **strongly typed** language, every variable has a defined type. Some of these types include:
* String, "Hello world!"
* Char, 'a'
* int, 3
* decimal, 1.5
* bool, True
## Compiler
C# is a strongly typed, compiled, object oriented language. Let's break this down.
## Strongly typed
In a **strongly typed** language, every variable has a defined type. Some of these types include:
* String, "Hello world!"
* Char, 'a'
* int, 3
* decimal, 1.5
* bool, True
## Compiler
A **compiler** converts the code you write into a format that your computer can understand. After you write C# and build it, the C# compiler (called Roslyn) will analyze your code to check for any errors.
---
# The basics
## 🌍 Hello World
Here's a piece of code that will print "Hello world!" to the console.
```csharp
@ -35,16 +43,20 @@ Console.WriteLine("Hello world!");
```
## Keywords
With C#, you use keywords like `using` and `Console`.
**Keywords** are predefined, reserved identifiers that have special meanings to the compiler.
## Accessing methods
The `. (DOT)` in `Console.WriteLine` allows us to access methods and properties. In this example, `Console` is a type that represents the console window. `WriteLine` is a method of the Console type that prints a line of text to that text console.
## Parameters
In this example, we use parentheses pass a string as a parameter to `Console.WriteLine`.
## 🚨 Challenge 1
In this example, we use parentheses pass a string as a parameter to `Console.WriteLine`.
## 🚨 Challenge 1
Time for your first challenge!
| # | Challenge | Solution | Duration | What you will learn | More information |
@ -52,40 +64,55 @@ Time for your first challenge!
1 | [Hello World Challenge](https://docs.microsoft.com/learn/modules/csharp-write-first/2-exercise-hello-world/?ns-enrollment-type=learningpath&ns-enrollment-id=learn.languages.csharp-first-steps)| N/A | 3 min | case sensitive, strings, comments | [Intro to C# Tutorial](https://docs.microsoft.com/dotnet/csharp/tour-of-csharp/tutorials/hello-world?WT.mc_id=csharpnotebook-35129-website), [C# documentation](https://docs.microsoft.com/dotnet/csharp/) |
## Variables
In C#, **variables** allow you to temporarily store a value in memory. In C#, you must declare a variable before using it.
In C#, **variables** allow you to temporarily store a value in memory. In C#, you must declare a variable before using it.
```csharp
var cSharp = "really cool";
```
In this example, we created a string called `cSharp`. You can use the var keyword to declare local variables without explicitly giving them a type.
Variable names can contain alphanumeric characters and underscores, but no special characters. They also cannot be keywords.
## 🚨 Challenge 2
| # | Challenge | Solution | Duration | What you will learn | More information |
|-| ------------------------------- | ------------------------------- | ----------- | -------------------------------------- | - |
2 | [Variables Challenge](https://docs.microsoft.com/learn/modules/csharp-literals-variables/6-challenge )|[Solution](https://docs.microsoft.com/learn/modules/csharp-literals-variables/7-solution)| 5 min | variables, data types, strings, ints, decimals | [String formatting tutorial](https://docs.microsoft.com/learn/modules/csharp-basic-formatting/), [C# documentation](https://docs.microsoft.com/dotnet/csharp/) |
# Syntax cheat sheet
## Semicolons
Every statement is ended by a semicolon
```csharp
Console.WriteLine("there is a ';' at the end of this statement");
```
## Comments
You can make comments by using 2 slashes
```csharp
// this is a comment is C#
```
## Case sensitive
C# is case sensitive! For example, a variable "cat" is completely different from a variable "CAT".
```csharp
var cat = "meow";
```
```csharp
var CAT = "rawr";
```
```csharp
var cat = "meow";
```
```csharp
var CAT = "rawr";
```
## Arithmetic Operators
These are probably familiar to you!
| symbol | what it does |
| --- | ------ |
@ -98,26 +125,30 @@ Variable names can contain alphanumeric characters and underscores, but no speci
| -- | decrement |
## 🚨 Challenge 3
| # | Challenge | Solution | Duration | What you will learn | More information |
|-| ------------------------------- | ------------------------------- | ----------- | -------------------------------------- | - |
3 | [Operating on numbers challenge](https://docs.microsoft.com/learn/modules/csharp-basic-operations/5-challenge)|[Solution](https://docs.microsoft.com/learn/modules/csharp-basic-operations/6-solution)| 2 min | ints, decimals | [Number operations tutorial](https://docs.microsoft.com/learn/modules/csharp-basic-operations/), [C# documentation](https://docs.microsoft.com/dotnet/csharp/) |
## Decision logic
In C#, you can build applications that employ decision-making logic so that your application performs different instructions based on a set of conditions. One way we do this is with an `if` statement. `if` statements are made up of three parts:
* The if keyword
* A Boolean expression between parenthesis ()
* A code block defined by curly braces { }
If there are multiple condition, you can utilize the `else if` and `else` statements. Basically, if the `if` statement fails, these other statements allow you to test against other conditions.
You can imagine this in the context of a rock⛰-paper📃-scissors✂ game. Imagine you chose rock⛰.
You can imagine this in the context of a rock⛰-paper📃-scissors✂ game. Imagine you chose rock⛰.
* `if` your opponent chooses scissors✂, then you will win
* `else if` your opponent also chooses rock⛰, then you will tie
* `else` your opponent chooses paper📃, then you will lose
Each possible decision your opponent could make leads to a different outcome.
## Boolean expressions
Booleans are expressions that return either `true` or `false`. They are often used to compare two or more things.
| symbol | what it does |
| --- | ---------- |
@ -129,18 +160,21 @@ Each possible decision your opponent could make leads to a different outcome.
| != | not equal |
## 🚨 Challenge 4
| # | Challenge | Solution | Duration | What you will learn | More information |
|-| ------------------------------- | ------------------------------- | ----------- | -------------------------------------- | - |
4 | [Decision logic challenge](https://docs.microsoft.com/learn/modules/csharp-if-elseif-else/4-challenge)|[Solution](https://docs.microsoft.com/learn/modules/csharp-if-elseif-else/5-solution)| 2 min | if, else if, else, booleans | [Boolean expressions tutorial](https://docs.microsoft.com/learn/modules/csharp-evaluate-boolean-expressions/1-introduction), [C# documentation](https://docs.microsoft.com/dotnet/csharp/) |
---
# Object Oriented Programming
C# is an object-oriented language.
Objects are defined by **Classes**. In other words, an **Object** is an instance of a class.
One way to think about this is that a class is like the blue prints for a house. The actual house that is built is an objects because it is an instance of this blue print.
## Properties and methods
Objects inherently have attributes. In C# we call these **properties**. The attributes of a house may be the number of doors, what color the house is painted, etc.
We can also define **methods** which describe what an object can do. For example, you can sell your house.
@ -152,6 +186,7 @@ The Properties of a house could be the number of doors it has or the color it's
A Method of our class is that we can sell our house 💸
Let's look at an example House class:
```csharp
// The namespace declaration provides a way to logically organize your classes
namespace Classes;
@ -168,8 +203,10 @@ public class House
}
}
```
## Constructor
We can define a **constructor** to allow us to create new House objects.
We can define a **constructor** to allow us to create new House objects.
```csharp
public House(string address, int squareFeet)
@ -178,7 +215,9 @@ public House(string address, int squareFeet)
this.Size = squareFeet;
}
```
When we create an object with `new` this constructor will be called.
```csharp
using Classes;
@ -187,18 +226,19 @@ var house = new House("123 Candy Cane Lane", 1500);
```
## The .NET Class Library
C# also has built in classes and functionality within the .NET Class Library. The .NET Class Library is a collection of thousands of classes containing tens of thousands of methods. These methods are created by Microsoft and are available for use in your applications. For example, when we called `Console.WriteLine` earlier, we were calling a method from the `System.Console` class. For a more in-depth overview, you can read up on the .NET Class Library in the [.NET documentation](https://docs.microsoft.com/dotnet/standard/class-library-overview).
## 🚨 Challenge 5
| # | Challenge | Solution | Duration | What you will learn | More information |
|-| ------------------------------- | ------------------------------- | ----------- | -------------------------------------- | - |
5 | [.NET Class Library challenge](https://docs.microsoft.com/learn/modules/csharp-call-methods/5-challenge)|[Solution](https://docs.microsoft.com/learn/modules/csharp-call-methods/6-solution)| 2 min | ints, decimals | [.NET documentation](https://docs.microsoft.com/dotnet/standard/class-library-overview), [C# documentation](https://docs.microsoft.com/dotnet/csharp/) |
# Bonus and more ways to connect
Want more practice with C#? The .NET team has you covered. Here's a few learning resources:
* C# Video Series on [Microsoft Docs](https://docs.microsoft.com/shows/CSharp-101/?WT.mc_id=dotnet-35129-website) or [YouTube](https://www.youtube.com/watch?v=Z5JS36NlJiU)
* Self Guided Tutorials on [Microsoft Learn](https://docs.microsoft.com/users/dotnet/collections/yz26f8y64n7k07)
* [Learn to Code Page](https://dotnet.microsoft.com/learntocode)