Java

// Hierarchical Inheritance in Java
class shape {
    float length, breadth, radius;
}

class rect extends shape {
    public rect(float l, float b) {
        length = l;
        breadth = b;
    }

    float rectangle_area() {
        return length * breadth;
    }
}

class circle extends shape {
    public circle(float r) {
        radius = r;
    }

    float circle_area() {
        return 3.14f * (radius * radius);
    }
}

class square extends shape {
    public square(float l) {
        length = l;
    }

    float square_area() {
        return (length * length);
    }
}

public class App {
    public static void main(String[] args) {

        rect o1 = new rect(2, 5);
        System.out.println("Area of Rectangle : " + o1.rectangle_area());

        circle o2 = new circle(5);
        System.out.println("Area of Circle : " + o2.circle_area());

        square o3 = new square(3);
        System.out.println("Area of Square : " + o3.square_area());

    }
}