Java/Def of Method/메소드정의

public static void main(String[] args) {
		System.out.println("좋은아침");
		Scanner sc = new Scanner(System.in);
		System.out.println("나이?");
		int age = 0;
		age = sc.nextInt();
		if (age > 40)
			System.out.println("꾸벅");
		else if (age > 30)
			System.out.println("까딱");
		else if (age > 20)
			System.out.println("어이");
		else if (age > 10)
			System.out.println("여어");
		sc.close();
	}

public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int age = 0;
		while (true) {
			System.out.println("좋은아침");
			System.out.println("나이?");
			age = sc.nextInt();

			if (age > 40)
				System.out.println("꾸벅");
			else if (age > 30)
				System.out.println("까딱");
			else if (age > 20)
				System.out.println("어이");
			else if (age > 10)
				System.out.println("여어");
			else if (age < 0)
				break;
		}
		sc.close();
	}

	public static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {

		while (true) {
			int ret = greeting();
			if (ret < 0)
				break;
		}
///greeting(); 단독으로사용가능

	}

	public static int greeting() {
		int age = 0;
		System.out.println("좋은아침");
		System.out.println("나이?");
		age = sc.nextInt();

		if (age > 40)
			System.out.println("꾸벅");
		else if (age > 30)
			System.out.println("까딱");
		else if (age > 20)
			System.out.println("어이");
		else if (age > 10)
			System.out.println("여어");
		return age;
	}

public static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {

		while (true) {
			int ret = getAge();
			greeting(ret);
			if (ret < 0)
				break;
		}

	}

	public static int getAge() {
		int age = 0;
		System.out.println("좋은아침");
		System.out.println("나이?");
		age = sc.nextInt();

		return age;
	}

	public static void greeting(int _age) {

		if (_age > 40)
			System.out.println("꾸벅");
		else if (_age > 30)
			System.out.println("까딱");
		else if (_age > 20)
			System.out.println("어이");
		else if (_age > 10)
			System.out.println("여어");

	}