Got it. Here’s **Phase 1 – Foundations (Lessons 1–5)** of your **C# Masterclass: From Zero to Hero**.
Everything below is formatted as ready-to-paste Markdown for Visual Studio Code or Obsidian.
Each lesson has objectives, explanations, annotated examples, and a mini-project.
When you’ve saved this section, I’ll continue straight to **Phase 2 (Lessons 6–9)**.
---
# 🧠 C# MASTERCLASS — PHASE 1 FOUNDATIONS
**Environment:** Visual Studio Code + .NET SDK 8
**Tone:** Technical Instructor
**Goal:** Learn core syntax, control flow, data handling and debugging.
---
## Lesson 1 – The First Line of C#
### Objectives
- Understand the structure of a C# program.
- Compile and run a console application in VS Code.
- Use `Console.WriteLine()` and `Console.ReadLine()`.
### Concepts
A minimal C# console program:
```csharp
using System;
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Hello, Genius!");
}
}
```
### Explanation
- `using System;` imports the base namespace that contains `Console`.
- `Main()` is the entry point; it must be `static`.
- `Console.WriteLine()` writes a line to stdout.
### Exercises
1. Replace the greeting with your own name.
2. Add a `Console.ReadLine()` so the window waits for input.
### Mini-Project — _Hello Genius App_
Ask for the user’s name and greet them.
```csharp
Console.Write("Enter your name: ");
string name = Console.ReadLine();
Console.WriteLine(
quot;Welcome to C#, {name}!");
```
---
## Lesson 2 – Variables of Power
### Objectives
- Understand data types and declarations.
- Perform basic operations and type conversion.
### Core Types
|Type|Example|Description|
|---|---|---|
|`int`|`int x = 5;`|Whole numbers|
|`double`|`double y = 2.5;`|Floating-point|
|`char`|`'A'`|Single character|
|`string`|`"text"`|Sequence of chars|
|`bool`|`true/false`|Logical values|
### Arithmetic Example
```csharp
int a = 10;
int b = 3;
double result = (double)a / b;
Console.WriteLine(result); // 3.3333
```
### Casting & Conversion
```csharp
string s = "42";
int value = int.Parse(s);
```
### Mini-Project — Unit Converter
Prompt for kilometres and convert to miles:
```csharp
Console.Write("Enter distance in km: ");
double km = double.Parse(Console.ReadLine());
double miles = km * 0.621371;
Console.WriteLine(quot;{km} km = {miles:F2} miles");
```
---
## Lesson 3 – Logic and Flow
### Objectives
- Apply `if`, `else if`, `switch`.
- Use loops: `for`, `while`, `foreach`.
- Combine conditions with logical operators.
### Conditional Example
```csharp
Console.Write("Enter age: ");
int age = int.Parse(Console.ReadLine());
if (age >= 18)
Console.WriteLine("Adult");
else if (age >= 13)
Console.WriteLine("Teenager");
else
Console.WriteLine("Child");
```
### Loop Examples
```csharp
for (int i = 1; i <= 5; i++)
Console.WriteLine(i);
int x = 0;
while (x < 5)
{
Console.WriteLine(x);
x++;
}
```
### Mini-Project — Number Guessing Game
```csharp
Random rnd = new Random();
int target = rnd.Next(1, 21);
int guess = 0;
Console.WriteLine("Guess a number 1-20:");
while (guess != target)
{
guess = int.Parse(Console.ReadLine());
if (guess < target) Console.WriteLine("Too low!");
else if (guess > target) Console.WriteLine("Too high!");
else Console.WriteLine("Correct!");
}
```
---
## Lesson 4 – Debugging Like a Detective
### Objectives
- Use breakpoints and step-through debugging in VS Code.
- Inspect variables and call stack.
- Understand common runtime errors.
### Tools
1. **Set Breakpoint:** Click left of line numbers.
2. **Run Debug:** `F5` → launch configuration `.vscode/launch.json`.
3. **Watch Variables:** Check values while stepping.
### Common Errors
|Error|Cause|Fix|
|---|---|---|
|`NullReferenceException`|Using a null object|Initialise before use|
|`FormatException`|Bad input to `Parse()`|Validate input|
|`IndexOutOfRangeException`|Invalid array index|Check bounds|
### Mini-Project — Bug Hunt
Broken code:
```csharp
string[] names = null;
for (int i = 0; i <= names.Length; i++)
Console.WriteLine(names[i]);
```
**Fix:**
```csharp
string[] names = { "Ana", "Ben", "Cara" };
for (int i = 0; i < names.Length; i++)
Console.WriteLine(names[i]);
```
Run under debugger and observe each iteration.
---
## Lesson 5 – Collections and LINQ
### Objectives
- Work with arrays and generic collections.
- Understand basic LINQ queries.
- Build a small in-memory data manager.
### Arrays
```csharp
int[] scores = { 90, 70, 80 };
foreach (int s in scores)
Console.WriteLine(s);
```
### Lists and Dictionaries
```csharp
using System.Collections.Generic;
List<string> students = new List<string> { "Ava", "Ben", "Cara" };
students.Add("Dan");
Dictionary<string, int> grades = new();
grades["Ava"] = 95;
```
### LINQ Basics
```csharp
using System.Linq;
var highScores = from g in grades
where g.Value >= 90
orderby g.Key
select g;
foreach (var g in highScores)
Console.WriteLine(quot;{g.Key}: {g.Value}");
```
### Mini-Project — Student Manager
Implement add/remove/display for students with scores.
```csharp
Dictionary<string, int> students = new();
while (true)
{
Console.Write("Command (add/list/quit): ");
string cmd = Console.ReadLine();
if (cmd == "add")
{
Console.Write("Name: ");
string name = Console.ReadLine();
Console.Write("Score: ");
int score = int.Parse(Console.ReadLine());
students[name] = score;
}
else if (cmd == "list")
{
foreach (var s in students.OrderByDescending(s => s.Value))
Console.WriteLine(quot;{s.Key} - {s.Value}");
}
else if (cmd == "quit") break;
}
```
---
### ✅ End of Phase 1 Summary
By now you can:
- Write, compile and debug C# programs.
- Use variables, operators and control structures.
- Handle collections and simple data queries.
Next: **Phase 2 – Object Power (Lessons 6–9)**
We’ll dive into Classes, OOP principles, and design patterns.
---
Confirm when you’ve copied Phase 1 into your workspace and I’ll immediately generate **Phase 2 (Lessons 6–9)**.