Getting our machines set up for C++ development, and introducing the fundamental building blocks of programming - variables.

Getting our computer set up so we can create and build C++ programs. Then, creating our very first application

Setting up a C++ Development Environment

An introduction to the building blocks of our software - objects, and the variables that can be associated with them.

Objects, Variables and Types

Creating variables to store and update the data that describes our objects.  We also introduce comments, allowing us to describe our code in plain language.

Creating Variables

An introduction to the different types of numbers in C++, and how we can do basic math operations on them.

Numbers

An overview of the fundamental true or false data type, how we can create them, and how we can combine them.

Booleans - `true` and `false` values

Explore how C++ programs store and manage numbers in computer memory, including integer and floating-point types, memory allocation, and overflow handling.

Types and Literals

Creating a tiny program using numbers and booleans, then adding some breakpoints so we can step through our code in a debugger.

Introduction to Debugging

Types and Variables

Discover how we can package our code into reusable functions that we can easily call.  Then, learn how we can use conditionals and loops to control the flow of our program.

An introduction to functions - reusable blocks of code that we can use to break our application into smaller pieces.

Creating and Calling Functions

An introduction to how our function calls create a call stack, and how we can navigate it in a debugger.

The Call Stack and Debugging Functions

Use booleans and if statements to make our functions and programs more dynamic, choosing different execution paths.

Conditional Logic

Learn an alternative way to write conditionals, which is often used when we want to take different paths based on a specific value

Switch Statements

Allow our functions to communicate with their caller by returning values when they complete

Function `return` Statements

Going into more depth on what is happening when a variable is used as a different type

Implicit Conversions and Narrowing Casts

Making our functions more useful and dynamic by providing them with additional values to use in their execution

Function Arguments and Parameters

Learn more about how and when we can access variables, by understanding the importance of the scope in which they exist.

Scope

Understand what function prototypes are, and learn how we can use them to let us order our code any way we want.

Forward Declarations

Learn how we can use loops to iterate over a block of code, executing it as many times as needed.

Loops

Learn how we can use the modulus operator to get the remainder of integer division, and some common use cases.

The Modulus Operator (`%`)

Put everything we've learned in this chapter to the test by creating a C++ version of the Fizz Buzz game.

Fizz Buzz

Learn how the `&&` and `||` operators are optimized with short-circuit evaluation, only evaluating expressions when necessary

Short-circuit Evaluation

Functions, Conditionals and Loops

Classes and structs are the fundamental feature of object oriented programming.  In this chapter, we will see how we can set them up, and how we can use them to create the custom types our program needs.

Learn how to define, instantiate, and utilize classes, understanding how they form the backbone of object-oriented programming.

Abstraction and Classes

A guide to encapsulation, class invariants, and controlling data access with `public` and `private` specifiers.

Encapsulation and Access Specifiers

Learn about special functions we can add to our classes, control how our objects get created and destroyed.

Constructors and Destructors

Discover the role of structs, how they differ from classes, and how to initialize them without requiring a constructor.

Structs and Aggregate Initialization

This lesson introduces operator overloading, a fundamental concept to create more intuitive and readable code by customizing operators for user-defined types

Operator Overloading

This lesson introduces Structured Binding, a handy tool for unpacking simple data structures

Structured Binding

Classes and Structs

See how we can use inheritance to organise our classes into a hierarchy, unlocking a massive range of possibilities for building more complex software

In this lesson, we explore C++ inheritance, guiding you through creating and managing class hierarchies to streamline your code

Inheritance

Learn about `protected` class members in C++, including how and when to use them in your code, especially in the context of inheritance and class design

Protected Class Members

This lesson introduces Member Initializer Lists, focusing on their advantages for performance and readability, and how to use them effectively

Member Initializer Lists

This lesson provides an in-depth exploration of using inherited methods and variables in C++, covering constructor calls, variable modification, and function shadowing

Working with Inherited Members

An introduction to working with memory, and how we represent memory locations using references and pointers

This lesson introduces references, explaining how they work, their benefits, and their role in performance and data manipulation

References

This lesson provides a thorough introduction to pointers in C++, covering their definition, usage, and the distinction between pointers and references

Pointers

Learn about the `this` pointer in C++ programming, focusing on its application in identifying callers, chaining functions, and overloading operators.

The `this` Pointer

Learn about an important consideration when returning pointers and references from functions

Dangling Pointers and References

Memory, References and Pointers

An introduction to polymorphism - the key tool that let us build more complex programs whilst keeping our code simple.

This lesson provides an in-depth look at function overloading in C++, covering its importance, implementation, and best practices

Function Overloading

Explore the concept of static casting in C++, including examples and best practices for converting data types at compile time

Static Casting

This lesson provides an introduction to virtual functions and overrides, focusing on their role in enabling runtime polymorphism

Virtual Functions and Overrides

Get to grips with downcasting in C++, including static and dynamic casts. This lesson provides clear explanations and practical examples for beginners

Downcasting

Polymorphism

Go deeper on what is happening when we build our software.  Learn how we can use the preprocessor to automatically modify our source code before it is compiled, and how the linker connects our program together.

Explore the essential concepts of C++ preprocessing, from understanding directives to implementing macros

Preprocessor Definitions

Discover how the `#include` directive helps us include library features and split our project across multiple files.

The `#include` Directive

Explore how header files and linkers streamline C++ programming, learning to organize and link our code effectively

Header Files

The Preprocessor and the Linker

Discover additional methods and techniques to keep our data and code organised.

Learn the essentials of using namespaces to organize your code and handle large projects with ease

Namespaces

Learn about Enums and how they offer an efficient way to handle predefined values in your code

Enums

This lesson introduces the `using` keyword in C++, focusing on namespaces, enums, and type aliasing

The `using` Keyword

Namespaces and Enums

Learn how to store collections of objects, and take control of how memory is managed

Explore the fundamentals of dynamic arrays with an introduction to `std::vector`

Dynamic Arrays using `std::vector`

Learn how to manage dynamic memory using unique pointers and the concept of memory ownership

Memory Ownership and Smart Pointers

Explore advanced techniques for managing object copying and resource allocation

Copy Constructors and Operators

Learn the techniques and pitfalls of manual memory management in C++

Managing Memory Manually

Arrays and Dynamic Memory

Techniques to simplify our code, making it easier to understand and maintain

This lesson covers how we can ask the compiler to infer what types we are using through the `auto` keyword

Automatic Type Deduction using `auto`

Learn the intricacies of using `const` and how to apply it in different contexts

Constants and `const`-Correctness

This lesson provides an overview of effective commenting strategies, including Javadoc style commenting for automated documentation

Effective Comments and Javadoc

This lesson introduces the concept of Style Guides and ClangFormat, focusing on how to achieve consistency in our code

Style Guides and Automatic Code Formatting

An introduction to static analysis tools, and how they can help beginners learn faster and improve code quality

Static Analysis

Explore the fundamentals of attributes, including `[[nodiscard]]`, `[[likely]]`, and `[[deprecated]]`

Attributes

Clean Code

A collection of lessons covering a variety of topics worth learning as a beginner

This lesson covers the basics of using randomness, with practical applications

Random Number Generation

Learn the basics of the chrono library and discover how to effectively manage durations, clocks, and time points

Dates, Times and Durations

A detailed guide to string formatting using C++20's `std::format()`, and C++23's `std::print()`

String Interpolation

Learn how to overload the `<<` operator, so our custom types can stream information directly to the console using `std::cout`

Overloading the `<<` Operator

This lesson introduces system calls, and how to use them to clear the terminal

System Calls and Terminal Management

This lesson introduces the fundamentals of capturing user input, using `std::cin` and `std::getline()`

User Input in the Terminal

Unravel the fundamentals of bitwise operators and bit flags in this practical lesson

Bitwise Operators and Bit Flags

Odds and Ends

This course is designed for beginners. We'll take you from the fundamentals and lay a solid foundation for creating real-world programs and learning more advanced concepts.

Become a software engineer with C++.  Starting from the basics, we guide you step by step along the way

This course teaches the fundamentals of C++ while instilling habits used by real-world developers. You'll gain practical experience with concepts that are the foundation of all modern programming.

No previous programming experience is needed - we start from the basics.

Start your Journey

We explain every line of code we're using, so you understand exactly what is happening.

Understand Every Line of Code

Everything we create is organised and implemented using modern, professional practices.

Use Professional Best Practices

We don't just explain what we're doing, but also why. This builds transferrable skills, so you can take what you've learnt and apply them to your own projects.

Focus on Transferrable Skills

No paywalls, no ads - the course is completely free with unlimited access

Free and Unrestricted Access

We break complex concepts into manageable steps, making even advanced topics feel approachable.

Step-by-Step Learning

What You'll Learn

Comprehensive course covering advanced concepts, and how to use them on large-scale projects.

Professional C++

If you're already familiar with the basics of C++ and object oriented programming, you may want to skip to the advanced course.  It starts with a quick summary of everything we cover here.

Already Familiar with Programming?

Intro to C++ Programming

<Excerpt>


Attributes are small statements we can add to our code to give the compiler, or other developers, guidance.  Attributes can be identified by the `[[` and `]]` that surround them.


There are many attributes we can use, and more are being added regularly.  We cover some of the most useful ones in this lesson:

- `[[nodiscard]]` indicates that we expect a function's return value to be used.  If it is discarded, the compiler will generate a warning
- `[[likely]]` and `[[unlikely]]` within conditional logic give the compiler guidance over which code path we expect to be taken, allowing it to optimize around the likely path
- `[[deprecated]]` gives other developers guidance that we'd prefer they not use a specific function or class, as we intend to remove it soon.

</Excerpt>


## The `[[nodiscard]]` Attribute


Let's consider the following code:


```c++
int Add(int x, int y) {
  return x+y;
}

int main() {
  Add(1, 2);//<w>
}
```


This is simple and compiles as expected.  However, if someone wrote code like this, they certainly made an error.


This is because the only thing our `Add` function does is return a value.  Yet, when `Add` is called, that return value is being ignored.


So, the call to `Add` isn't doing anything.  The developer probably misunderstood how our function works and is about to introduce a bug, or may just be wasting resources.


If we annotate the `Add` function with a `[[nodiscard]]` attribute, our program still works as expected, but the compiler now helpfully warns us of the issue:


```c++
[[nodiscard]]//<h>
int Add(int x, int y) {
  return x+y;
}

int main() {
  Add(1, 2);//<w>
}
```


```c++
//<o>
warning: Ignoring return value of function declared with 'nodiscard' attribute
```


<Aside>


### Function Side Effects


Specifically, `[[nodiscard]]` is designed to prevent us from discarding the return value of a function that doesn't have any _**side effects**_.


Side effects are things that the function does to modify the state of our program, beyond just returning a value.  Some examples of side effects include:

- Logging into the console
- Modifying variables outside the scope of the function - this can include modifying arguments that were passed by reference
- Calling some other function that has side effects

If a function has side effects, it typically isn't appropriate to mark it as `[[nodiscard]]`, as the caller may be calling the function just for those side effects.


</Aside>


## The `[[likely]]` and `[[unlikely]]` Attributes


When we're creating conditional logic, sometimes one of our branches is much more likely to be followed.  When we know that, we can provide that insight to the compiler, using `[[likely]]`:


```c++
void StartQuest(Character* Player) {
  if (Player->IsAlive()) [[likely]] {
    // ...
  }
  // ...
}
```


Similarly, we can inform the compiler that a condition is unlikely to be true using the `[[unlikely]]` attribute:


```c++
void Resurrect(Character* Target) {
  if (Target->IsAlive()) [[unlikely]] {
    // ...
  }
  // ...
}
```


When the compiler knows a path is going to be very commonly used within our function, it can optimize the compilation of that function accordingly.  This results in a performance improvement.


Additionally, other developers reading our code can get a sense of the expected context. In the previous example, our code suggests that it is possible that our `Resurrect` function could be given a `Target` that is already alive, but it's not likely.


<Aside>


### Profile-Guided Optimization (PGO)


A more advanced form of this technique commonly used on larger projects is _**profile-guided optimization**_ or PGO.


Our program might have a function that is called hundreds or thousands of times per second, whilst another is rarely ever called.  The compiler should arrange our code to optimize the performance of the function that is called more frequently.


However, the compiler doesn't inherently know how often our functions will be called at runtime.


With PGO, we first compile our project with additional data collection enabled.  We then run our program and use it as normal, whilst the data collection generates a detailed profile of what code paths are being executed.


Once we have enough data, we stop running our program and store the generated profile.


This profile includes insights like how often each function is called, which branches are most commonly taken, and how often loops iterate.


We then compile it again, but this second compilation uses the profile to guide the compilation process on what execution paths it should optimize for.


</Aside>


## The `[[deprecated]]` Attribute


The final attribute we want to cover is `[[deprecated]]`.   When something is "deprecated", it still works, but we'd rather people not use it.


For example, we might want to remove a function that has a subtle bug, performance issue, or is just difficult for us to maintain.  However, that function may be used in hundreds or thousands of other places.  This is particularly common when we're working on a large project with colleagues, or working on a library that is being used in other projects.


Instead of attempting to remove or change a function that is used in many parts of the code, including parts of the code that are "owned" by other developers or other teams, it's instead common to mark the function as _**deprecated**_. 


A deprecated function can still be used and it works as it always has but, when it is used, a warning will be emitted asking the developer to update their code to stop using it and implement their logic in some other way.  Then, after some time, and hopefully after everyone has heeded the warning and stopped using the function, we can remove it entirely.


We can mark a function as deprecated using the `[[deprecated]]` attribute:


```c++
[[deprecated]]
void StartQuest(Character* Player) {
  // ...
}
```


Now, code that calls this function will still work, but they will get a compiler warning:


```c++
//<o>
'StartQuest' is deprecated
```


Generally, we will want to give more information - for example, what should the consumer use instead?  We can update our `[[deprecated]]` attribute to include a message:


```c++
[[deprecated(
  "StartQuest(Character*) will be removed "
  "soon - switch to StartQuest(QuestJournal*)"
)]]
void StartQuest(Character* Player) {
  // The function we want to remove
  // ...
}

void StartQuest(QuestJournal* Journal) {
  // The function we want to replace it with
  // ...
}
```


```c++
//<o>
warning C4996: 'StartQuest': StartQuest(Character*) will be removed soon - switch to StartQuest(QuestJournal*)
```


<Aside>


### Visual Studio C4996 Error


By default, Visual Studio's compiler treats invocations of a `[[deprecated]]` function as an error, rather than a warning.  This prevents us from building our project.


We can change this by opening the Project menu from the top bar, and then visiting _Properties >  C/C++ > Command Line._  On this panel, under _Additional Options_, we can add: `/sdl /w34996` to have the compiler treat this error as a warning instead.


</Aside>


There are many more attributes we can use.  Additionally, compilers often introduce their own, non-standard attributes, which we can include in our code if we're using that compiler.


However, this summary introduced the most common and useful attributes.


## Summary


In this lesson, we've explored the concept of attributes.  The key things we learned included:

- Learned the use of `[[nodiscard]]` to prevent discarding important return values and to catch potential errors.
- Understood how `[[likely]]` and `[[unlikely]]` attributes guide the compiler for optimization by indicating the expected path in conditional logic.
- Explored the `[[deprecated]]` attribute to manage the evolution of code by marking functions or entities for future removal.
- Gained insights into the importance of compiler-guided optimization and how attributes contribute to efficient code execution.
- Discussed the concept of function side effects and when it's appropriate to use certain attributes.

<Preview>


### Randomness


In the upcoming lesson, we learn how to generate randomness in C++.  This allows us to introduce non-deterministic results in our program, which we demonstrate in the context of a combat system for a role-playing game.  The key topics we'll cover include**:**

- **Understanding Random Number Generation**: Learn the basics of how random numbers are generated in C++ and their applications.
- **Seeding Random Number Generators**: Understand how to seed a random number generator, including how to control the seed to allow for repeatable results.
- **Different Random Engines in C++**: Understand the purpose of random number engines, like  `std::mt19937`.
- **Distributions and Their Uses**: Explore different types of distributions (like uniform, normal, etc.) and how they shape random data for various use cases.

</Preview>

Attribute specifier sequence (since C++11)

C++ attribute: likely, unlikely (since C++20)

C++ attribute: nodiscard (since C++17)

C++ attribute: deprecated (since C++14)

C++ attribute: carries_dependency (since C++11)

C++ attribute: fallthrough (since C++17)

C++ attribute: maybe_unused (since C++17)

C++ attribute: no_unique_address (since C++20)

{CPP}Master C++ attributes with this beginner-friendly guide

{CPP}C++ Attributes: [[nodiscard]], [[likely]], and [[deprecated]]

The `[[likely]]` and `[[unlikely]]` Attributes

Attributes

Understanding the Basics

Practical Applications

Common Mistakes

Next Steps

Additional Resources

Assessment Preparation

Intro to C++ Programming