//  Data Structures with Java by John R. Hubbard
//  Copyright McGraw-Hill, 2001
//  Example 6.6 on page 115
//  Iterative Towers of Hanoi

public class Ex0606
{ public static void main(String[] args)
  { hanoi(3,'A','B','C');  // play the game with 3 disks
  }

  private static void hanoi(int n, char x, char y, char z)
  { java.util.Stack stack = new java.util.Stack();
    stack.push(new Quad(n,x,y,z));
    while (!stack.empty())
    { Quad quad = (Quad)stack.pop();
      n = quad.n;
      x = quad.a;
      y = quad.b;
      z = quad.c;
      if (n == 1) System.out.println
        ("Move top disk from peg " + quad.a + " to peg " + quad.c);
      else
      { stack.push(new Quad(n-1,y,x,z));
        stack.push(new Quad(1,x,y,z));
        stack.push(new Quad(n-1,x,z,y));
      }
    }
  }
}

class Quad
{ public int n;
  public char a, b, c;
  public Quad(int n, char a, char b, char c)
  { this.n = n; this.a = a; this.b = b; this.c = c; 
  }
}