Rewrite the fib method in Listing 18.2 using iterations. To compute fib(n) without recursion, you need to obtain fib(n - 2) and fib(n - 1) first. Let f0 and f1 denote the two previous Fibonacci numbers. The current Fibonacci number would then be f0 + f1. The algorithm can be described as follows:

Write a test program that prompts the user to enter an index and displays its Fibonacci number.

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f0 = 0; // For fib(0) f1 = 1; // For fib(1) for (int i = 1; i <= n; i++) { currentFib = f0 + f1; f0 = f1; f1 currentFib; // After the loop, currentFib is fib(n) 1 import java.util.Scanner; 2 3 public class ComputeFibonacci { 4 /** Main method */ public static void main(String] args) { // Create a Scanner Scanner input = new Scanner(System.in); System.out.print("Enter an index for a Fibonacci number: "); int index = input.nextInt(); 10 11 12 13 14 // Find and display the Fibonacci number System.out.println("The Fibonacci number at index " + index + " is " + fib(index)); 15 16 17 18 19 /** The method for finding the Fibonacci number */ public static long fib(long index) { if (index == 0) // Base case return 0;