你应该有一个宠物类，其中包含狗、猫和鸟的子类。变量应与适当的类相关联，在适当时定义为私有的，并具有适当的函数来访问变量。将打印描述函数重写为虚拟函数。编写一个 main 函数，该函数创建至少包含一只鸟、一只狗和一只猫的宠物向量或数组，然后循环并输出每个宠物的描述。

好的，我可以帮你编写这个程序。下面是完整的代码实现：

#include <iostream>
#include <vector>

using namespace std;

class Pet {
protected:
    string name;
    int age;
public:
    Pet(string n, int a) : name(n), age(a) {}
    virtual void printDescription() {
        cout << "I am a pet named " << name << ", and I am " << age << " years old." << endl;
    }
};

class Dog : public Pet {
private:
    string breed;
public:
    Dog(string n, int a, string b) : Pet(n,a), breed(b) {}
    void setBreed(string b) { breed = b; }
    string getBreed() { return breed; }
    void printDescription() {
        cout << "I am a dog named " << name << ", and I am " << age << " years old. My breed is " << breed << "." << endl;
    }
};

class Cat : public Pet {
private:
    bool isIndoor;
public:
    Cat(string n, int a, bool i) : Pet(n,a), isIndoor(i) {}
    void setIsIndoor(bool i) { isIndoor = i; }
    bool getIsIndoor() { return isIndoor; }
    void printDescription() {
        cout << "I am a cat named " << name << ", and I am " << age << " years old. ";
        if (isIndoor) {
            cout << "I am an indoor cat." << endl;
        } else {
            cout << "I am an outdoor cat." << endl;
        }
    }
};

class Bird : public Pet {
private:
    bool canFly;
public:
    Bird(string n, int a, bool f) : Pet(n,a), canFly(f) {}
    void setCanFly(bool f) { canFly = f; }
    bool getCanFly() { return canFly; }
    void printDescription() {
        cout << "I am a bird named " << name << ", and I am " << age << " years old. ";
        if (canFly) {
            cout << "I can fly." << endl;
        } else {
            cout << "I cannot fly." << endl;
        }
    }
};

int main() {
    vector<Pet*> pets;
    Dog dog("Buddy", 3, "Golden Retriever");
    Cat cat("Fluffy", 2, true);
    Bird bird("Tweety", 1, true);
    pets.push_back(&dog);
    pets.push_back(&cat);
    pets.push_back(&bird);
    for (Pet* pet : pets) {
        pet->printDescription();
    }
    return 0;
}

这个程序定义了一个 `Pet` 类和它的三个子类：`Dog`、`Cat` 和 `Bird`。所有的子类都继承了 `Pet` 的成员变量 `name` 和 `age`，并且都重写了 `printDescription()` 函数，以便输出适当的描述信息。

在 `main()` 函数中，我们创建了一个 `vector`，并向其中添加了一只狗、一只猫和一只鸟。然后我们循环遍历这个 `vector`，并对每个元素调用 `printDescription()` 函数，以便输出每个宠物的描述信息。

运行程序后，输出如下：

I am a dog named Buddy, and I am 3 years old. My breed is Golden Retriever.
I am a cat named Fluffy, and I am 2 years old. I am an indoor cat.
I am a bird named Tweety, and I am 1 years old. I can fly.

可以看到，程序成功输出了每个宠物的描述信息。