C++ Inheritance and Polymorphism

A class can inherit from another. A virtual function lets the right version run through a base-class pointer.

ExampleC++

#include <iostream>
#include <memory>
#include <vector>
using namespace std;

class Animal {
 public:
  virtual string speak() const { return "..."; }
  virtual ~Animal() = default;
};

class Dog : public Animal {
 public:
  string speak() const override { return "woof"; }
};

class Cat : public Animal {
 public:
  string speak() const override { return "meow"; }
};

int main() {
  vector<unique_ptr<Animal>> pets;
  pets.push_back(make_unique<Dog>());
  pets.push_back(make_unique<Cat>());
  pets.push_back(make_unique<Animal>());
  for (const auto &p : pets) cout << p->speak() << endl;
  return 0;
}

Output

woof
meow
...

Quick check

Which keyword enables polymorphism on a base-class function?

virtualstaticinline

Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.

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