// Define a Person class, version 3.

public class Person
{
    // Declare instance variables.
    private String name;
    private char gender;
    private int age;

    // Define noarg constructor.
    public Person( )
    {
        name = "Unknown";
        gender = 'U';
        age = -1;
    }

    // Define parameterized constructor.
    public Person(String theName, char theGender, int theAge)
    {
        // Validate theName.
        if (!theName.equals(""))
            name = theName;
        else
            name = "Unknown";

        // Validate theGender.
        if (theGender == 'F' || theGender == 'M')
            gender = theGender;
        else
            gender = 'U';

        // Validate theAge.
        if (theAge >= 0)
            age = theAge;
        else
            age = -1;   
    }

    public String getName( )
    {
        return name;
    }

    public char getGender( )
    {
        return gender;
    }

    public int getAge( )
    {
        return age;
    }

    public void hasBirthday( )
    {
        if (age != -1)
            age++;
    }

    public void display( )
    {
        System.out.println("Name: " + name);
        System.out.println("Gender: " + gender);
        System.out.println("Age: " + age);
    }

    public String toString( )
    {
        return name + " " + gender + " " + age;
    }

    // Two Person objects are equal if 
    // their names are the same.
    public boolean equals(Object other)
    {
        String otherName = ((Person) other).getName( );
        if (name.equals(otherName))
            return true;
        else
            return false;
    }

    // One Person object is greater than 
    // another if its age is greater.
    public int compareTo(Object other)
    {
        int otherAge = ((Person) other).getAge( );
        if (age > otherAge)
            return 1;
        else if (age < otherAge)
            return -1;
        else
            return 0;
    }    
}