/* File: FibObject.java - March 2018 */
package l04;

/**
* Compute and display the Fibonacci number of the input argument
* using a recursive algorithm. The problem with 'double recursion'
* is avoided by using a special purpose object which holds a consecutive
* pair of Fibonacci numbers. The recursion is actually hidden in the
* constructor of a FibPair object!
*
* Sample usage: java l04.FibObject 10
*
* @author Michael Albert
*
*/
public class FibObject{

  public static void main(String[] args) {
    int n = Integer.parseInt(args[0]);
    System.out.println("Fib(" + n + ") = " + (new FibPair(n)).currFib);  
  }


  private static class FibPair {
  
    long prevFib;
    long currFib;
    
    FibPair(int n) {
      if (n == 0) {
        this.prevFib = 0;
        this.currFib = 1;
      } else {
        FibPair prevPair = new FibPair(n-1);
        this.prevFib = prevPair.currFib;
        this.currFib = prevPair.currFib + prevPair.prevFib;      
      }
    
    }
    
  }

}