Fibonacci

// ***************************************************************************************/
// File Name: JRT_Fibonacci.java            Author: Justin Trubela                        /
// Section: 03                                                                            /
//                                                                                        /
// Purpose:       4.Write an array that contains the first 20 using a calculation         /
//                      to generate the numbers                                           /
//The program prints the first 20 Fibonacci numbers in the array                                XX
//                                                  separated by a comma and a space.           XX
//
//Asks the user which of the numbers in this series of 20 he wants to see                       XX
//      and prompts for an integer input - a number between 1 and 20(inclusive).
//      So if the user wants to see the fifth (5th) number of the Fibonacci series
//          the user would input the integer 5 in response to the prompt.
//
//Checks that the user has not input a number lower than 1 or higher than 20                    XX
//
//Prints in response to the user entry "The nth Fibonacci number is  X",                        XX
//     where n is the number input by the user and X is the  nth Fibonacci number.
//     (Array indexes for the elements of the array start at 0),
//     Example: If user inputs "6" in response to the prompt,
//    the program would print "The 6th Fibonacci number is 5." (without the quotes)
//****************************************************************************************/

import java.util.Scanner;

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

        Scanner scan = new Scanner(System.in);
        int limit = 20;
        long[] series = new long[limit];

        //create first 2 series elements
        series[0] = 0;
        series[1] = 1;

        long f1=0,f2=1,f3;

        for (int i= 0; i<20; i++) {
            f3=f1+f2;
            series[i]=f3;
            f1=f2;
            f2=f3;
            if(i<series.length-1) {
                System.out.print(series[i]+", ");
                }
            else {
                System.out.print(series[i]+".");
            }

        }
        System.out.println("\n\nEnter the number of the Fibonacci Series would you like to see:");
        int userInputFibNum = scan.nextInt();
        while (userInputFibNum < 1 || userInputFibNum > 20) {
            System.out.println("Number must be between 1 and 20");
            System.out.println("\n\nEnter the number of the Fibonacci Series would you like to see:");
            userInputFibNum = scan.nextInt();
        }

        String postfix = "th";
        if(userInputFibNum == 1) {
            postfix = "st";
        }
        else if(userInputFibNum == 2) {
            postfix = "nd";
        }
        else if(userInputFibNum == 3) {
            postfix = "rd";
        }

        System.out.println("The "+userInputFibNum + postfix + " Fibonacci number is: " + series[userInputFibNum-1]);


        scan.close();
    }
}