Classes (Object-Oriented Programming)

This lesson covers the basics of writing a class in C++. It's for anyone searching "C++ class usage."

A class bundles data (member variables) and logic (member functions) together. Use public: to specify which members can be used from outside the class.

The example defines class Animal, with a member variable name and a member function, speak(), that returns a sound.

A common early mistake is forgetting to write public:. In C++, a class's members are private by default, so you need to explicitly mark anything you want to use from outside as public:.

In real projects, classes are used to represent data that bundles state and behavior together — a game character, or an element in a simulation.

📖 Reference code

#include <iostream>
#include <string>

class Animal {
public:
    std::string name;
    std::string speak() {
        return name + " is barking.";
    }
};

int main() {
    Animal dog;
    dog.name = "Rex";
    std::cout << dog.speak() << std::endl;
    return 0;
}

✍️ Your code

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🧪 This site can't compile or run C++ directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).