/**
 * Test of a simple Fibonacci number calculator.<br />
 *
 * @author Wayne Eberly
 */

public class Fibonacci1 {

	/**
	 * Test of a simple Fibonacci number calculator.
	 */
	public static void main(String[] args) {
		System.out.println("Test of a Simple Fibonacci Number Calculator");
		System.out.println("");
		for (int i=0; i <= 40; i++){
			System.out.print("n: ");
			System.out.printf("%2d", i);
			System.out.print(";     nth Fibonacci number: ");
			System.out.printf("%10d", fib(i));
			System.out.println("");
		}
	}

	/**
	 * Computes a specified Fibonacci number as a long integer by a direct
	 * application of the recursive definition.
	 * 
	 * <p>
	 *  <strong>Precondition:</strong>
	 *           <code>i</code> is a nonnegative integer.<br />
	 *  <strong>Postcondition:</strong>
	 *           Value returned is the <code>i</code><sup>th</sup>
	 *           Fibonacci number.
	 * </p>
	 * 
	 * @param i Index of the Fibonacci number to be calculated
	 * @return  The ith Fibonacci number
	 * @throws IllegalArgumentException If the input integer is negative
	 *
	 */
	 public static long fib(int i) {
	 	if (i<0) {
	 		throw new IllegalArgumentException("Negative Input: " + i);
	 	} else {					// i >= 0
	 		if (i==0) {
	 			return 0;
	 		} else {				// i >= 1
	 			if (i==1) {
	 				return 1;
	 			} else {			// i >= 2
	 				return fib(i-1) + fib(i-2);
	 			}
	 		}
	 	}
	 }
}