// Source code example for "A Practical Introduction
// to Data Structures and Algorithm Analysis"
// by Clifford A. Shaffer, Prentice Hall, 1998.
// Copyright 1998 by Clifford A. Shaffer

import java.io.*;

// Driver class for testing factorial function
class Factmain {

// Compute factorial
static long fact(int n) { // Must have n < 21 to fit in long
  Assert.notFalse((n >= 0) && (n < 21), "Input out of range");
  Stack S = new AStack(n-1); // Make stack just big enough
  while (n > 1) S.push(new Integer(n--));
  long result = 1;
  while (!S.isEmpty())
    result = result * ((Integer)S.pop()).longValue();
  return result;
}

  // Main routine for factorial driver class
  public static void main(String args[]) throws IOException {
    for(int i = 1; i<25; i++)
    System.out.println("Factorial of " + i
                       + " is " + fact(i));
    System.in.read();
  }

} // class Rfactmain