JAVA

package tutorial1;
public class Main() {
  public static void main (String[] args) {
    Dog tim = new Dog ("tim", 4);
    tim.speak();
    tim.setAge(10);
  }
}

Dog.java
package tutorial1;
public class Dog {
  private String name;
  private int age;
  public Dog(String name, int age) {
    this.name = name;
    this.age = age;
  }
  public void speak() {
    System.out.println("hey"+this.name+"is lookie" + this.age);
  }
  public void setAge(int age) {
    this.age = age;
  }
}

---

public class Main {
  public static void main(String[] args) {
    Cat tim = new Cat("tim", 18, 100);
    Cat bob = new Cat("bob", 18);
    Cat joe  = new Cat("joe"); //age, food가 설정되지않았어도 cat에서 없어도 받는 함수를 만들었으니 지정한 값을 받아온다.
    tim.speak(); // Dog의 클래스에서 가져옴.
    bob.speak();
    joe.speak();
  }
}

public class Cat extends Dog
  private int food;
  public Cat(String name, int age, int food) {
    super(name, age);
    this.food = food;
  }
  public Cat(String name, int age) {
    super(name, age);
    this.food = 50;
  }
  public Cat(String name) {
    super(name, 0);
    this.food = 50;
  }
}

---

package tutorial1;
public class Car implements Vehicle{
  private int gear;
  private int speed;
  public void changeGear(int gear) {
    this.gear = gear;
  }
  public void speedUp(int change) {
    this.speed += change;
  }
  public void speedDown(int change) {
    this.speed -= change;
  }
  public void display() {
    System.out.println("Hey"+this.speed);
    out();
  }
}

package tutorial1;
public interface Vehicle { //forcus on interface 
  final int gears = 5;
  void changeGear(int a);
  void speedUp(int a);
  void slowDown(int a);
  default void out() {
    System.out.println("Default method");
  }
  static int math (int b) {
    return b + 9;
  }
}

package tutorial1;
public class main {
  public static void main(String[] args) {
    Car ford = new Car();
    ford.speedUp(10);
    ford.changeGear(2);
    ford.display();

    int x= Vehicle.math(5);
    System.out.println(x); //Vehicle에서 만들었던걸 쓸수 있다.
  }
}