//QuadString class
//Hold 4 strings
//Demonstrates Object methods: toString, equals, and clone
//9/13/2006


public class QuadString {
	
	//instance variables:
	private String one;
	private String two;
	private String three;
	private String four;
	
	public QuadString(String one, String two){
		//constructor: has default values for two and three
		this.one = one;
		this.two = two;
		this.three = "word3";
		this.four = "word4";
	}
	
	public String toString() {
		//returns a String representation of the Object
		String returnStr = "one is " + this.one + "\n";
		returnStr += "two is " + this.two + "\n";
		returnStr += "three is " + this.three + "\n";
		returnStr += "four is " + this.four + "\n";
		return returnStr;
	}
	
	public boolean equals(Object other){
		//compares this object of QuadString to another
		//note we do not need else if since it returns at any point that it discovers they are not equal
		if (!(other instanceof QuadString))
			return false;
		
		//cast the Object other in the QuadString ot
		//alternatively we could cast each use of other (not fun)
		QuadString ot = (QuadString)other;
			
		if (!(this.one.equals(ot.one)))
			return false;
		if (!(this.two.equals(ot.two)))
			return false;
		if (!(this.three.equals(ot.three)))
			return false;
		if (!(this.four.equals(ot.four)))
			return false;
		
		//all strings are equal so they must be the same
		return true;
	}
	
	public Object clone() {
		//create a new object which is the same as "this"
		QuadString other = new QuadString(this.one, this.two);
		return other;
	}
	
	public static void main (String [] args) {
		//main class method being used to test class/objects
		QuadString qs = new QuadString("hello world", "string");
		
		//the following lines are logically equivalent: (toString is called in the first as well)
		System.out.println(qs);
		System.out.println(qs.toString());
		
		//get a copy of qs (qs2 is it's own object)
		QuadString qs2 = (QuadString)qs.clone();
		//note clone returns an Object, so we must cast it
		
		if (qs == qs2){
			//this will not be printed because they are not the same exact instance/object of QuadString
			System.out.println("They are equal with == (not true)");
		}
		
		if (qs.equals(qs2)){
			//this is true because the equals method compares the content
			System.out.println("They're equal with equals method");
		}
	}
}