IterativeFibonacciAtIndex.java

// Christopher Yonek
// Compute Fibonacci (Iteration)

import java.util.Scanner;
public class IterativeFibonacciAtIndex {

 public static void main(String args[]) {
 Scanner input = new Scanner(System.in);
 System.out.print("Enter an index for the Fibonacci number: ");
 int index = input.nextInt();
 long startTime = System.nanoTime();
 System.out.println("Fibonacci number at index " + index + " is " + fibonacciLoop(index));
 long elapsedTime = System.nanoTime() - startTime;
 System.out.println(elapsedTime);
 }

 public static int fibonacciLoop(int numAtEnd) { //use loop
 int secondPrevNum, prevNumber = 0, numberGiven = 1;

 for (int i = 1; i < numAtEnd ; i++) {
 secondPrevNum = prevNumber;
 prevNumber = numberGiven;
 numberGiven = secondPrevNum + prevNumber;
 }
 return numberGiven;
 }
}