Learn C++ Online: Free Compiler and IDE
Write, compile, and run C++ code in your browser. GCC 12, instant compilation, debugger included.
# Learn C++ Online: Free Compiler and IDE
C++ remains one of the most powerful and widely-used programming languages in the world. From game engines and operating systems to high-frequency trading platforms and embedded devices, C++ is everywhere. But getting started with C++ locally can be a chore — installing a compiler, configuring build systems, and wrestling with platform-specific toolchains.
YaliCode gives you a fully configured C++ environment in your browser. GCC 12, instant compilation, a built-in debugger, and zero setup.
Why Learn C++ in the Browser?
Setting up a local C++ development environment involves several steps that have nothing to do with actually learning C++:
With YaliCode, you skip all of that. Open your browser, select the C++ template, and write code. The compiler and runtime are already configured in a sandboxed Docker container running Debian with GCC 12 and g++.
Getting Started
1. Open [yalicode.dev/editor](https://yalicode.dev/editor)
2. Select the C++ template from the template picker
3. Write your code in the editor
4. Press Ctrl+Enter to compile and run
That is it. No installation, no configuration, no waiting.
How Compilation Works
Unlike interpreted languages such as Python or JavaScript, C++ requires a separate compilation step before execution. YaliCode makes this process transparent by showing you both stages in the console output.
When you press Ctrl+Enter, the following happens behind the scenes:
1. Your code is sent to our execution API
2. The compiler (`g++ -std=c++17`) runs inside a sandboxed container
3. If compilation succeeds, the resulting binary executes immediately
4. Both compiler output and program output appear in the console panel
If your code has errors, you will see the GCC error messages with line numbers and descriptions — the same output you would get on your local machine. Our AI error explanation feature can break down cryptic template errors into plain English.
```cpp
// Compiler output example
main.cpp:7:15: error: expected ';' after expression
int x = 42
^
;
```
The console panel separates compiler messages (shown in gray) from your program's standard output (white) and standard error (red), so you always know what is coming from where.
Code Examples
Hello World
The classic starting point. This compiles and runs in under two seconds on YaliCode.
```cpp
#include <iostream>
int main() {
std::cout << "Hello from YaliCode!" << std::endl;
return 0;
}
```
Working with Vectors
Modern C++ (C++17 is the default standard) gives you powerful standard library containers. Here is a practical example using `std::vector`:
```cpp
#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
int main() {
std::vector<int> scores = {85, 92, 78, 96, 88, 73, 91};
// Sort the scores
std::sort(scores.begin(), scores.end());
// Calculate the average
double average = std::accumulate(scores.begin(), scores.end(), 0.0) / scores.size();
std::cout << "Sorted scores: ";
for (int s : scores) {
std::cout << s << " ";
}
std::cout << "\nAverage: " << average << std::endl;
// Find scores above 90
auto it = std::lower_bound(scores.begin(), scores.end(), 90);
std::cout << "Scores >= 90: ";
for (; it != scores.end(); ++it) {
std::cout << *it << " ";
}
std::cout << std::endl;
return 0;
}
```
Classes and Object-Oriented Programming
C++ is a multi-paradigm language, and OOP is one of its core strengths. Here is a simple class hierarchy:
```cpp
#include <iostream>
#include <string>
#include <vector>
#include <memory>
class Shape {
public:
virtual ~Shape() = default;
virtual double area() const = 0;
virtual std::string name() const = 0;
};
class Circle : public Shape {
double radius;
public:
Circle(double r) : radius(r) {}
double area() const override { return 3.14159265 * radius * radius; }
std::string name() const override { return "Circle"; }
};
class Rectangle : public Shape {
double width, height;
public:
Rectangle(double w, double h) : width(w), height(h) {}
double area() const override { return width * height; }
std::string name() const override { return "Rectangle"; }
};
int main() {
std::vector<std::unique_ptr<Shape>> shapes;
shapes.push_back(std::make_unique<Circle>(5.0));
shapes.push_back(std::make_unique<Rectangle>(4.0, 6.0));
shapes.push_back(std::make_unique<Circle>(3.0));
for (const auto& shape : shapes) {
std::cout << shape->name() << " - Area: " << shape->area() << std::endl;
}
return 0;
}
```
This example uses smart pointers (`std::unique_ptr`), virtual functions, and the standard library — all fully supported on YaliCode's GCC 12 compiler.
Built-In Debugger
Debugging C++ code in the browser is something most online compilers cannot do. YaliCode's trace-based debugger lets you set breakpoints and inspect variable values at each step.
To use it:
1. Click the gutter next to a line number to set a breakpoint
2. Click Debug (or press the debug button in the toolbar)
3. The debugger panel shows variable values captured at each breakpoint hit
For C++ specifically, the debugger instruments your code to capture state at breakpoints. You can see local variables, loop counters, and object members — enough to track down most logic bugs without reaching for GDB.
Comparison with Local Setup
| Feature | Local (GCC + VS Code) | YaliCode |
|---------|----------------------|----------|
| Setup time | 15-60 minutes | 0 minutes |
| Compiler | GCC/Clang (your version) | GCC 12 (g++, C++17) |
| Debugger | GDB/LLDB (full featured) | Trace-based (variable inspection) |
| Build systems | CMake, Make, Meson | Single-file compilation |
| Multi-file projects | Full support | Supported via project files |
| Performance profiling | Valgrind, perf, etc. | Not available |
| Sharing | Zip and email | Share a URL |
| Cost | Free (your hardware) | Free tier available |
The honest answer: for large multi-file projects, production work, or performance-critical development, you still want a local setup. YaliCode is ideal for learning, quick testing, sharing code snippets, and prototyping algorithms.
Use Cases
Learning C++
If you are working through a textbook or online course, YaliCode lets you focus on the language instead of tooling. Type the example, run it, modify it, see what happens. The AI error explanation is especially helpful when you hit a wall with template metaprogramming errors.
Quick Testing
Need to verify how `std::move` works? Check the behavior of integer overflow? Test a sorting algorithm? Open [yalicode.dev/editor](https://yalicode.dev/editor), paste your code, and run it. No project setup required.
Technical Interviews
Practicing for coding interviews in C++? YaliCode supports standard input (`std::cin`) through a stdin dialog, so you can test your solutions with custom input just like you would on a competitive programming platform.
Teaching
If you run a C++ course or tutorial, share your examples as YaliCode project links. Students can open them, fork them, and experiment — no need to troubleshoot their local compiler installations.
Supported C++ Features
YaliCode's GCC 12 compiler supports the full C++17 standard, including:
Start Writing C++ Now
No signup required for basic usage. Open [yalicode.dev/editor](https://yalicode.dev/editor), pick C++, and compile your first program in seconds. When you are ready to save and share your work, create a free account to get project storage and shareable URLs.
Explore all 23 supported languages at [yalicode.dev](https://yalicode.dev).