Introduction to C++

C++ is a fast, compiled language that combines C's direct control over the machine with powerful tools for building large programs: classes, templates, a rich standard library and automatic resource management. It runs game engines, browsers, databases, trading systems and much of the software where performance matters most.

Where C++ is used

Games and graphics — Unreal Engine and most AAA game engines, 3D tools, VR.
Browsers and operating system components — Chrome, Firefox and large parts of Windows and macOS.
Infrastructure — databases such as MySQL and MongoDB, compilers (LLVM), and high-performance servers.
Finance and science — low-latency trading, simulations, machine-learning frameworks such as the cores of PyTorch and TensorFlow.
Embedded and real-time systems — cars, robots, drones, medical devices.

A first look

C++

#include <iostream>
#include <string>
#include <vector>

int main() {
    std::vector<std::string> languages{"C", "C++", "Rust"};
    for (const auto& name : languages) {
        std::cout << "Hello from " << name << "!\n";
    }
}

Output

Hello from C!
Hello from C++!
Hello from Rust!

This program stores three strings in a vector — a list that manages its own memory — and prints a greeting for each. Lesson 3 explains every part.

C++ and C

C++ began as "C with classes", and almost all C code is still valid C++. But modern C++ is written very differently from C:

Task	C style	Modern C++ style
Text	`char` arrays and `strcpy`	`std::string`
Lists	Arrays plus `malloc`/`realloc`	`std::vector`
Memory	`malloc` and `free` by hand	Containers and smart pointers that free themselves
Errors	Return codes	Exceptions, `std::optional`, `std::expected`
Generic code	Macros, `void *`	Templates and concepts

You don't need to know C to take this course. If you do, the C course gives useful background on memory and pointers.

What makes C++ special

Zero-overhead abstractions. High-level features like classes, templates and algorithms compile down to code as fast as hand-written low-level code.
RAII. Objects clean up after themselves when they go out of scope — memory, files, locks — without a garbage collector.
Multi-paradigm. Procedural, object-oriented, generic and functional styles all work, and mix freely.
Huge ecosystem. Decades of libraries, tools and expertise.

The trade-off is complexity: C++ is a big language with sharp edges inherited from C. This course focuses on the modern, safer subset you should actually use.

A short history

Bjarne Stroustrup started "C with Classes" at Bell Labs in 1979; it was renamed C++ in 1983 (++ is the increment operator). Since the first ISO standard in 1998 the language has been updated every three years:

Standard	Highlights
C++98/03	The first standard: classes, templates, the STL containers and algorithms
C++11	"Modern C++": `auto`, lambdas, move semantics, smart pointers, range-`for`, threads
C++14 / C++17	Refinements; `optional`, `variant`, `string_view`, structured bindings
C++20	Concepts, ranges, `std::format`, `span`, coroutines, modules
C++23	`std::print`, `std::expected`, more ranges
C++26	In progress: reflection, contracts and more

This course teaches C++20, which current GCC, Clang and MSVC support well, and covers the newer C++23 additions in lesson 50.

How this course works

Every example was compiled with a real compiler (Clang 17, using -std=c++20 -Wall -Wextra -pedantic) and run, and the output shown is exactly what it printed. The Try it yourself boxes let you edit an example and copy it to compile on your own computer — set that up in the next lesson.

Try it yourself

Add your own favourite languages to the list and run it again.

Output

I want to learn C++
I want to learn Python
I want to learn JavaScript

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