Seminar_2/Task_9

package Seminar_2;

import java.util.Scanner;

public class Task_9 {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);

        Task_9 myApp = new Task_9();

        boolean exit = false;

        while (!exit) {
            System.out.printf("%n1. Calculate all integers up to the position of X%n2. Calculate X position on the fibonacci sequence%nChoice : ");
            int choice = in.nextInt();
            if (choice == 1) {
                System.out.printf("%nCalculates and prints X numbers in the fibonacci sequence%nEnter X : ");
                int numberToBeCalculated = in.nextInt();
                if (numberToBeCalculated >= 3) {
                    myApp.fibonacciCalculationAll(numberToBeCalculated);
                } else if (numberToBeCalculated == 2) {
                    System.out.println("1 1");
                } else if (numberToBeCalculated == 1) {
                    System.out.println("1");
                } else {
                    System.out.println("Please enter a valid answer next time.");
                }
            } else if (choice == 2) {
                System.out.printf("%nCalculates X position in the fibonacci sequence%nEnter X : ");
                int numberToBeCalculated = in.nextInt();
                if (numberToBeCalculated >= 3) {
                    myApp.fibonacciCalculationOne(numberToBeCalculated);
                } else if (numberToBeCalculated == 2) {
                    System.out.println("1");
                    System.out.println("The number in the position " + 2 + " in the fibonacci sequence is : " + 1);
                } else if (numberToBeCalculated == 1) {
                    System.out.println("1");
                    System.out.println("The number in the position " + 1 + " in the fibonacci sequence is : " + 1);
                } else {
                    System.out.println("Please enter a valid answer next time.\n");
                }
            } else if (choice == 3) {
                exit = true;
                System.out.println("Have a nice day");
            } else {
                System.out.println("Please enter a valid choice");
            }
        }
    }

    private long fibonacciCalculationAll(int numberOfCalculations) {
        numberOfCalculations -= 2;
        long number = 1;
        long lastNumber = 1;
        long doubleLastNumber = 1;
        System.out.print("1 1 ");
        for (int i = 0; i < numberOfCalculations; i++) {
            doubleLastNumber = lastNumber;
            lastNumber = number;
            number = lastNumber + doubleLastNumber;
            System.out.printf("%d ", number);
        }
        System.out.println();
        return number;
    }

    private void fibonacciCalculationOne(int numberOfCalculations) {
        numberOfCalculations -= 2;
        long number = 1;
        long lastNumber = 1;
        long doubleLastNumber = 1;
        for (int i = 0; i < numberOfCalculations; i++) {
            doubleLastNumber = lastNumber;
            lastNumber = number;
            number = lastNumber + doubleLastNumber;
        }
        System.out.printf("The number in the position %d in the fibonacci sequence is : %d%n", numberOfCalculations+2, number);
    }

}