How do you inherit from a class in C++?

Write class Derived : public Base { … };, and call the base constructor in the initializer list.

* Public inheritance is an "is-a" relationship: Truck and Bicycle each derive from Vehicle, call its constructor, and override getName(). *

class Truck : public Vehicle {
public:
    Truck() : Vehicle(6) {}          // call base constructor
private:
    virtual string getName() { return "Truck"; }
};

class Bicycle : public Vehicle {
public:
    Bicycle() : Vehicle(2) {}
private:
    virtual string getName() { return "Bicycle"; }
};

Key points:

• : public Base is public inheritance (the most common kind) — it models an "is-a" relationship (a Truck is a Vehicle)
• The derived constructor must initialize the base part by calling the base constructor in its initializer list
• Marking methods virtual lets a subclass override them and enables polymorphism

Go deeper:

• Derived classes — cppreference — inheritance and how the access specifier changes what's inherited.
• Inheritance (OOP) — Wikipedia — the "is-a" concept across languages.