/*
 COMP 1006 - Day 04
 Extra Class (extra stuff about static)
 mjh-2013
*/


/*
  Mock complex number class in which you have to ask 
  to add a number 3 times before you are allowed to 
  perform an addition.
*/

public class Extra{

	// private attributes can only be accessed from
	// methods inside the class (static or not)
	// We cannot access them directly from other classes
		
	private int re_;   // real and imaginary parts are "private"
	private int im_;   // so that calling calling program cannot
	                   // directly access them (and beat out asking game)


	private static int count = 0; 	// keeps track of how many times 
									// calling program asks to add


	// static method for asking to add
	public static void please(){
		// please() is a method in Extra so it can access
		// the static variable count
		count += 1;
		System.out.println("Thank you for asking. You current count is " + count);
	}


	public String toString(){
		// toString() is a special method that, when defined, 
		// allows us to nicely print something when we try to 
		// print an instance (object) 

		// it can access all attributes of the Extra class
		// (including the static ones)
		return "(" + this.re_ + "," + this.im_ + ")";
	}	


 	// method for adding two Extra numbers 
	public Extra plus(Extra other){
		if (count < 3){
			System.out.println("you need to ask 3 times!");
			return new Extra(0,0);
		}else{
			// using "this" for count is forbidden
			// because it does not belong to any instance (object)
			count -= 3;             // using "this" here is forbidden
			
			this.re_ += other.re_;  // using "this" here is optional
			this.im_ += other.im_;
			return this;   // using "this" here is needed
		}
	}


	// static method for addition
	// there is no calling object with this method
	public static Extra add(Extra first, Extra second){
		if (count < 3){  // no "this" for count
			System.out.println("you need to ask 3 times!");
			return new Extra(0,0);
		}else{
 			count -= 3;    // no "this" for count
			Extra answer = new Extra();
			answer.re_ = first.re_ + second.re_;
			answer.im_ = first.im_ + second.im_;
			return answer;
		}
	} 


	// constructors for complex numbers	
	Extra(){
		// zero paramater constructor
		re_ = 0;  // could have put this.re_ = re;  
		im_ = 0;  // could have put this.im_ = im; 
	}
	
	Extra(int re, int im){
		// we could access and modify the static variable
		// count here, but we have no need
		
		this.re_ = re;   // I will use "this" when I write code  
		this.im_ = im;   // You can do either.  Just be consistent
	}
	
}