//
// Supporting material for lecture 14
// - private static variables (population/pop)
//

public class Person {
    private String firstName;
    private String surName;
    private int age;
    private Person spouse;
    private static int pop = 0; // population

    public Person(String firstName,String surName,int age){
	this.firstName = firstName;
	this.surName   = surName;
	this.age       = age;
	spouse         = null;
	pop++;
    }

    public Person(String firstName,String surName){
	this.firstName = firstName;
	this.surName   = surName;
	this.age       = 0;
	spouse         = null;
	pop++;
    }

    public String toString(){
	String s = firstName + " " + surName + " " + " age " + age;
	if (spouse != null) 
	    s = s + " married to " + spouse.firstName;
	return s;
    }

    public boolean isMarried(){return spouse != null;}
    public int getAge(){return age;}
    public String getName(){return firstName + " " + surName;}
    public void marry(Person x){this.spouse = x;x.spouse = this;}
    public int getPop(){return pop;} // get population
}

//
// NOTES
// - we have 2 constructors
// - naming convention of Classes, instance variables, methods such as toString, etc
// - this
// - null !!!
//
// Exercise: 
// Make instance variables and appropriate methods so that 
// we can make y a father of x, and z the mother of x
// also so that we can access father and grandfather of x
// Ultimately we have a family tree (or is it a tree?)
//