Hierarchical Inheritance in OOPs

 #include <iostream>

using namespace std;

// hierarchical inheritance

class Animal {

public:

    string eat;

    string breathe;

};

class Bird : public Animal {

public:

    string fly;

};

class Fish : public Animal {

public:

    string swim;

};

class Mammal : public Animal {

public:

    string walk;

};

int main() {

    Bird b1;

    Fish f1;

    Mammal m1;

    b1.fly = "bird flies..";

    f1.swim = "fish swims..";

    m1.walk = "mammal walks..";

    cout << b1.fly << endl;

    cout << f1.swim << endl;

    cout << m1.walk << endl;

    return 0;

}