FibonacciTest.java

//import java.util.Scanner;
//import java.text.DecimalFormat;

public class FibonacciTest {
    public static void main(String[] args) {

        //Scanner in = new Scanner(System.in);
        //System.out.print("Enter number for fibonacci: ");
        //int input = in.nextInt();

        int input = 46;

        if (input<=46) {
            System.out.println( "Using iteration:");
            System.out.println( "The "+input+"th fibonacci is "+fibonacci( input));
            System.out.println( "Using recursion:");
            System.out.println( "The "+input+"th fibonacci is "+getNthFibonacci( input));
        } else {
            System.out.println("Number too big! Max is 46");
        } // end if

    } // end main()

    // fast method
    public static int fibonacci(int input) {
        int a = 0;
        int b = 1;

        for (int i = 0; i < input; i++) {
            a += b;
            b = a - b;
            if (a<0) return 0;
            //System.out.println("Term "+(i+1)+": "+a);
        }
        return a;
    } // end fibonacci()

    // get the nth Fibonacci number using recursion: sloooow for numbers 40-46
    public static int getNthFibonacci(int n) {
        if (n < 3) return 1;
        return getNthFibonacci(n-2) + getNthFibonacci(n-1);
    } // end getNthFibonacci()

} // end class FibonacciTest