Challenge: Smart Pointer Zoo

Lab C++ Intermediate 20 points

Keep animals in a vector<unique_ptr<Animal>>. Animal has a name, a virtual string kind() const and a virtual int legs() const. Make Bird (2 legs) and Dog (4 legs). Read n lines like bird Tweety, then print each as Tweety the bird and finally Total legs: X.

Input

n, then n lines: kind name.

Output

One line per animal, then the total.

Example

Input

3
bird Tweety
dog Rex
bird Polly

Output

Tweety the bird
Rex the dog
Polly the bird
Total legs: 8

Sample input available Sample output available

Editor

C++

Hints

#include <memory> and use make_unique<Bird>(name).

Loop with for (const auto& a : zoo) and use a->...

Solution explanation

The vector owns the animals; when it is destroyed at the end of main, every animal is deleted automatically.

Show solution

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

class Animal {
protected:
    string name;
public:
    Animal(string n) : name(n) {}
    virtual ~Animal() {}
    string getName() const { return name; }
    virtual string kind() const = 0;
    virtual int legs() const = 0;
};

class Bird : public Animal {
public:
    Bird(string n) : Animal(n) {}
    string kind() const override { return "bird"; }
    int legs() const override { return 2; }
};

class Dog : public Animal {
public:
    Dog(string n) : Animal(n) {}
    string kind() const override { return "dog"; }
    int legs() const override { return 4; }
};

int main() {
    int n;
    cin >> n;
    vector<unique_ptr<Animal>> zoo;
    for (int i = 0; i < n; i++) {
        string kind, name;
        cin >> kind >> name;
        if (kind == "bird") {
            zoo.push_back(make_unique<Bird>(name));
        } else {
            zoo.push_back(make_unique<Dog>(name));
        }
    }
    int total = 0;
    for (const auto& a : zoo) {
        cout << a->getName() << " the " << a->kind() << "\n";
        total += a->legs();
    }
    cout << "Total legs: " << total << "\n";
    return 0;
}

Output

Answer