JAvaルーチン練習(BirthDateクラスと簡単なテストプログラム)

public class Test {
	public static void main(String[] args) {
		Test test = new Test();
		int date = 9;
		BirthDate d1 = new BirthDate(7, 7, 1970);
		BirthDate d2 = new BirthDate(1, 1, 2000);
		test.change1(date);
		test.change2(d1);
		test.change3(d2);
		
		System.out.println("date = " + date);
		d1.display();
		d2.display();
	}	
	
	public void change1(int i) {
		i = 1234;
	}
	
	public void change2(BirthDate b) {
		b = new BirthDate (22, 2, 2004);
	}
	
	public void  change3(BirthDate b) {
		b.setDay(22);
	}
		
	
}


class BirthDate {
	private int day;
	private int year;
	private int month;
	
	BirthDate(int d, int y, int m) {
		day = d;
		year = y;
		month = m;
	}
	
	public void setDay(int day) {
		this.day = day;
	}
	
	public int getDay() {
		return day;
	}
	
	public void setYear(int year) {
		this.year = year;
	}
	
	public int getYear() {
		return year;
	}
	
	public void setMonth(int month) {
		this.month = month;
	}
	
	public int getMonth() {
		return month;
	}
	
	public void display() {
		System.out.println(day + "-" + month + "-" + year);
	}
	
	
}