Inheritance

This lesson covers inheritance, a mechanism for creating a new class that inherits an existing class's functionality. It's for anyone searching "C++ inheritance usage."

Use the form class Child : public Parent { ... } to inherit. A subclass can use its parent class's members directly, add its own members, and override (replace) member functions.

The example inherits class Animal with class Dog : public Animal, overriding speak() with dog-specific content.

A common early mistake is forgetting the public keyword. Writing class Dog : Animal without public defaults to private inheritance, which can produce unintended behavior.

In real projects, a common pattern is inheriting a class with a shared trait, like "animal," while implementing a different sound for each specific animal.

📖 Reference code

#include <iostream>
#include <string>

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

class Dog : public Animal {
public:
    Dog(std::string n) : Animal(n) {}
    std::string speak() override {
        return name + ": Woof!";
    }
};

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

✍️ Your code

Type your code, then press "Run"

🧪 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).