Vorislik va interfeyslar

public class Vorislik {
    public static void main(String[] args) {
        new Talaba("Husanboy", 25, "Informatika").tanishtir();
        new Oqituvchi("Nodira", 40, "Matematika").tanishtir();
    }
}

class Shaxs {
    protected final String ism;
    protected final int yosh;

    Shaxs(String ism, int yosh) {
        this.ism = ism;
        this.yosh = yosh;
    }

    void tanishtir() {
        System.out.println("Men " + ism + ", " + yosh + " yoshdaman");
    }
}

class Talaba extends Shaxs {
    private final String yonalish;

    Talaba(String ism, int yosh, String yonalish) {
        super(ism, yosh);
        this.yonalish = yonalish;
    }

    @Override
    void tanishtir() {
        super.tanishtir();
        System.out.println("  " + yonalish + " yo'nalishi talabasiman");
    }
}

class Oqituvchi extends Shaxs {
    private final String fan;

    Oqituvchi(String ism, int yosh, String fan) {
        super(ism, yosh);
        this.fan = fan;
    }

    @Override
    void tanishtir() {
        System.out.println("Men " + ism + ", " + fan + " o'qituvchisiman");
    }
}

public class Shakllar {
    public static void main(String[] args) {
        Shakl[] shakllar = {new Doira(5), new Togritortburchak(4, 6)};

        for (Shakl shakl : shakllar) {
            System.out.printf("%-16s maydoni = %.2f%n",
                    shakl.nomi(), shakl.maydon());
        }
    }
}

abstract class Shakl {
    abstract String nomi();

    abstract double maydon();
}

class Doira extends Shakl {
    private final double radius;

    Doira(double radius) {
        this.radius = radius;
    }

    @Override
    String nomi() {
        return "Doira";
    }

    @Override
    double maydon() {
        return Math.PI * radius * radius;
    }
}

class Togritortburchak extends Shakl {
    private final double eni;
    private final double boyi;

    Togritortburchak(double eni, double boyi) {
        this.eni = eni;
        this.boyi = boyi;
    }

    @Override
    String nomi() {
        return "To'rtburchak";
    }

    @Override
    double maydon() {
        return eni * boyi;
    }
}

import java.util.ArrayList;
import java.util.List;

public class Interfeyslar {
    public static void main(String[] args) {
        Yozuvchi[] chiqishlar = {new Konsolga(), new Xotiraga()};

        for (Yozuvchi y : chiqishlar) {
            y.yoz("Salom");
            y.yoz("Dunyo");
        }

        for (Yozuvchi y : chiqishlar) {
            if (y instanceof Xotiraga x) {
                x.korsat();
            }
        }
    }
}

interface Yozuvchi {
    void yoz(String matn);

    default void yozKatta(String matn) {
        yoz(matn.toUpperCase());
    }
}

class Konsolga implements Yozuvchi {
    @Override
    public void yoz(String matn) {
        System.out.println("[konsol] " + matn);
    }
}

class Xotiraga implements Yozuvchi {
    private final List<String> qatorlar = new ArrayList<>();

    @Override
    public void yoz(String matn) {
        qatorlar.add(matn);
    }

    void korsat() {
        System.out.println("[xotira] " + qatorlar.size()
                + " qator: " + String.join(", ", qatorlar));
    }
}

public class Default {
    public static void main(String[] args) {
        Salomlovchi s = ism -> System.out.println("Salom, " + ism);

        s.salomlash("Husanboy");
        s.salomlashRasmiy("Nodira Karimovna");
    }
}

interface Salomlovchi {
    void salomlash(String ism);

    default void salomlashRasmiy(String ism) {
        salomlash("hurmatli " + ism);
    }
}

public class KopInterfeys {
    public static void main(String[] args) {
        Hujjat h = new Hujjat("Hisobot");
        h.saqla();
        h.chop();
    }
}

interface Saqlanadigan {
    void saqla();
}

interface ChopEtiladigan {
    void chop();
}

class Hujjat implements Saqlanadigan, ChopEtiladigan {
    private final String nom;

    Hujjat(String nom) {
        this.nom = nom;
    }

    @Override
    public void saqla() {
        System.out.println(nom + " saqlandi");
    }

    @Override
    public void chop() {
        System.out.println(nom + " chop etildi");
    }
}

public class Tekshirish {
    public static void main(String[] args) {
        Object[] narsalar = {new Doira(2), new Kvadrat(3), "matn"};

        for (Object narsa : narsalar) {
            if (narsa instanceof Shakl shakl) {
                System.out.printf("Shakl, maydoni %.2f%n", shakl.maydon());
            } else {
                System.out.println("Shakl emas: "
                        + narsa.getClass().getSimpleName());
            }
        }
    }
}

abstract class Shakl {
    abstract double maydon();
}

class Doira extends Shakl {
    private final double r;

    Doira(double r) {
        this.r = r;
    }

    @Override
    double maydon() {
        return Math.PI * r * r;
    }
}

class Kvadrat extends Shakl {
    private final double t;

    Kvadrat(double t) {
        this.t = t;
    }

    @Override
    double maydon() {
        return t * t;
    }
}