Inheritance and types of inheritance

class Animal {
    String name;

    void eat() {
        System.out.println(name + " is eating");
    }
}

class Dog extends Animal {
    void bark() {
        System.out.println(name + " says Woof");
    }
}

public class Main {
    public static void main(String[] args) {
        Dog d = new Dog();
        d.name = "Sheru";
        d.eat();
        d.bark();
    }
}

class Person { }

class Student extends Person { }

public class Main {
    public static void main(String[] args) {
        Student s = new Student();
        System.out.println("Class: " + s.getClass().getSimpleName());
        System.out.println("Parent: " + s.getClass().getSuperclass().getSimpleName());
        System.out.println("Grandparent: " + s.getClass().getSuperclass().getSuperclass().getSimpleName());
    }
}

class Shape {
    String colour;
}

class Rectangle extends Shape {
    int length, width;

    int area() {
        return length * width;
    }
}

class Square extends Rectangle {
    void setSide(int side) {
        length = side;
        width = side;
    }
}

public class Main {
    public static void main(String[] args) {
        Square sq = new Square();
        sq.colour = "red";
        sq.setSide(6);
        System.out.println("A " + sq.colour + " square of area " + sq.area());
    }
}

class Device { }
class Computer extends Device { }
class Laptop extends Computer { }

public class Main {
    public static void main(String[] args) {
        Laptop l = new Laptop();
        Device d = new Device();
        System.out.println("laptop is Computer: " + (l instanceof Computer));
        System.out.println("laptop is Device: " + (l instanceof Device));
        System.out.println("laptop is Object: " + (l instanceof Object));
        System.out.println("device is Laptop: " + (d instanceof Laptop));
    }
}

class Employee {
    String name;

    void describe() {
        System.out.print(name + " - ");
    }
}

class Developer extends Employee {
    String language;
}

class Tester extends Employee {
    String tool;
}

class Designer extends Employee {
    String software;
}

public class Main {
    public static void main(String[] args) {
        Developer d = new Developer();
        d.name = "Neha";
        d.language = "Java";
        Tester t = new Tester();
        t.name = "Imran";
        t.tool = "Selenium";
        Designer g = new Designer();
        g.name = "Pooja";
        g.software = "Figma";

        d.describe(); System.out.println("codes in " + d.language);
        t.describe(); System.out.println("tests with " + t.tool);
        g.describe(); System.out.println("designs in " + g.software);
    }
}

class Account {
    private double balance;

    public void deposit(double amount) {
        if (amount > 0) balance += amount;
    }

    public double getBalance() {
        return balance;
    }
}

class SavingsAccount extends Account {
    void addInterest(double ratePercent) {
        double interest = getBalance() * ratePercent / 100;
        deposit(interest);
    }
}

public class Main {
    public static void main(String[] args) {
        SavingsAccount s = new SavingsAccount();
        s.deposit(20000);
        s.addInterest(3.5);
        System.out.println("Balance after interest: " + s.getBalance());
    }
}

class Vehicle {
    static int count;
    Vehicle() { count++; }
}

class Car extends Vehicle {
    static int count;
    Car() { count++; }
}

class SportsCar extends Car {
    static int count;
    SportsCar() { count++; }
}

public class Main {
    public static void main(String[] args) {
        new Vehicle(); new Vehicle();
        new Car();
        new SportsCar(); new SportsCar();
        System.out.println("Vehicle constructor ran " + Vehicle.count + " times");
        System.out.println("Car constructor ran " + Car.count + " times");
        System.out.println("SportsCar constructor ran " + SportsCar.count + " times");
    }
}

class Account {
    private final String accountNo;
    protected double balance;

    Account(String accountNo) {
        this.accountNo = accountNo;
    }

    void deposit(double amount) {
        if (amount > 0) balance += amount;
    }

    String summary() {
        return accountNo + ": Rs " + balance;
    }
}

class SavingsAccount extends Account {
    SavingsAccount(String no) { super(no); }

    void addYearlyInterest() {
        balance += balance * 0.04;
    }
}

class CurrentAccount extends Account {
    private static final double OVERDRAFT = 10000;

    CurrentAccount(String no) { super(no); }

    boolean withdraw(double amount) {
        if (balance - amount < -OVERDRAFT) return false;
        balance -= amount;
        return true;
    }
}

public class Main {
    public static void main(String[] args) {
        SavingsAccount s = new SavingsAccount("SB-01");
        s.deposit(50000);
        s.addYearlyInterest();
        System.out.println(s.summary());

        CurrentAccount c = new CurrentAccount("CA-07");
        c.deposit(5000);
        System.out.println("Withdraw 12000: " + c.withdraw(12000));
        System.out.println(c.summary());
    }
}

class Employee {
    private final String id;
    private final String name;

    Employee(String id, String name) {
        this.id = id;
        this.name = name;
    }

    void printSlip(double pay) {
        System.out.printf("%s %-6s Rs %,.2f%n", id, name, pay);
    }
}

class FullTimeEmployee extends Employee {
    private final double basic;

    FullTimeEmployee(String id, String name, double basic) {
        super(id, name);
        this.basic = basic;
    }

    double monthlyPay() {
        return basic + basic * 0.40;
    }
}

class ContractEmployee extends Employee {
    private final double hourlyRate;
    private final int hours;

    ContractEmployee(String id, String name, double hourlyRate, int hours) {
        super(id, name);
        this.hourlyRate = hourlyRate;
        this.hours = hours;
    }

    double monthlyPay() {
        return hourlyRate * hours;
    }
}

public class Main {
    public static void main(String[] args) {
        FullTimeEmployee f = new FullTimeEmployee("E101", "Anil", 40000);
        ContractEmployee c = new ContractEmployee("C207", "Sara", 600, 120);
        f.printSlip(f.monthlyPay());
        c.printSlip(c.monthlyPay());
    }
}

class DeliveryVehicle {
    private final String regNo;
    private final int maxKg;

    DeliveryVehicle(String regNo, int maxKg) {
        this.regNo = regNo;
        this.maxKg = maxKg;
    }

    boolean canCarry(int kg) {
        return kg <= maxKg;
    }

    String getRegNo() { return regNo; }
}

class Bike extends DeliveryVehicle {
    Bike(String regNo) { super(regNo, 20); }
}

class Van extends DeliveryVehicle {
    private final boolean commercialLicence = true;

    Van(String regNo) { super(regNo, 800); }

    boolean needsCommercialLicence() { return commercialLicence; }
}

public class Main {
    public static void main(String[] args) {
        Bike b = new Bike("MH-02-1111");
        Van v = new Van("MH-02-9999");
        int[] parcels = {15, 120};
        for (int kg : parcels) {
            System.out.println(kg + " kg -> bike " + b.canCarry(kg) + ", van " + v.canCarry(kg));
        }
        System.out.println(v.getRegNo() + " needs commercial licence: " + v.needsCommercialLicence());
    }
}