/* File: BadRec.java - March 2018 */
package l06;

/**
* Illustrating the horrors that arise when you have recursion inside loops!
* The recursive function we're trying to compute is defined by:
*
* B(1) = 1
* B(n) = 1*B(1) + 2*B(2) + ... + (n-1)*B(n-1)
* 
* Sample usage: java l06.BadRec 3 
*
* @author Michael Albert
*
*/

public class BadRec{

  static int calls = 0;

  public static void main(String[] args) {
    long n = Long.parseLong(args[0]);
    System.out.println("B(" + n + ") = " + b(n));
    System.out.println("Calls required " + calls);
  }

  public static long b(long n) {
    calls++;
    if (n == 1) return 1;
    long result = 0;
    for(int i = 1; i < n; i++) {
      result += i*b(i);
    }
    return result;
  }

}