1.

#include <iostream>

using namespace std;
class Animal
{
private:
    int id;
public:
    Animal(){}
    Animal(int id):id(id)
    {}
    virtual void show()
    {
        cout << "动物园门牌号:" << id << endl;
    }
};
class Houzi:public Animal
{
private:
    string name;
public:
    Houzi(){}
    Houzi(int i,string n):Animal(i),name(n)
    {}
    void show()
    {
        cout << "呀呼" << endl;
    }
};
class Dog:public Animal
{
private:
    string name;
public:
    Dog(){}
    Dog(int i,string n):Animal(i),name(n)
    {}
    void show()
    {
        cout << "叫叫叫" << endl;
    }
};
class Kunkun:public Animal
{
private:
    string name;
public:
    Kunkun(){}
    Kunkun(int i ,string n):Animal(i),name(n)
    {}
    void show()
    {
        cout << "坤你太美" << endl;
    }
};
int main()
{
    Houzi h(123,"wzg");
    h.show();
    Dog d(123,"gswzg");
    d.show();
    Kunkun k(123,"cxk");
    k.show();
    return 0;
}

2.

#include <iostream>

using namespace std;
template <typename T>
void fun(T &a,T &b)
{
    T t;
    t=a;
    a=b;
    b=t;
}
int main()
{
    int a=10;
    int b=2;
    char c='1',d='2';
    fun(a,b);
    cout << a << endl;
    cout << b << endl;
    fun(c,d);
    cout << c << endl;
    cout << d << endl;
    return 0;
}

3