전화번호 관리 프로그램01

public class PhoneInfo
{
private String name;
private String phoneNumber;
private String birthday;

public PhoneInfo(String name, String phoneNumber, String birthday)
{
	this.name = name;
	this.phoneNumber = phoneNumber;
	this.birthday = birthday;
}
public PhoneInfo(String name, String phoneNumber)
{
	this(name, phoneNumber, null);
}
public void showPhoneInfo()
{
	System.out.println("이름 : " + name);
	System.out.println("전화번호 : " + phoneNumber);
	if(birthday != null)
		System.out.println("생년월일 : " + birthday);
}

}
public class PhoneInfoMain
{
public static void main(String[] args)
{
PhoneInfo pInfo1=new PhoneInfo("홍길동","12345678","19990232");
PhoneInfo pInfo2=new PhoneInfo("홍길순","12345678");
pInfo1.showPhoneInfo();
pInfo2.showPhoneInfo();
}
}