Need help working with the fibonacci sequence in java

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I'm currently trying to get the following output for my code that I'll provide later on:

Example
Enter an integer (1-46): 2

The 2nd number in the Fibonacci sequence is: 1

I have to insure the suffice "nd, st, th" is in the output at well. Below is the code I've created so far:

Java

import java.util.*;

public class Somethingpart2 {

	public static void main(String[] args) {

		Scanner kbd = new Scanner(System.in);

		//Variable Declaration 
		int number;
		long Fibnumber;
		Boolean accepted, limit;

		//Beginning of user input for the Fibonacci sequence 
		System.out.print("Enter an integer (1-46): ");
		number = kbd.nextInt();

		Fibnumber = Math.round(Math.pow((1+Math.sqrt(5))/2, number) / Math.sqrt(5)); 
		accepted = number >= 1 && number <= 46;
		limit = number == Fibnumber;


		if (accepted) {
			do {
				Fibnumber = Math.round(Math.pow((1+Math.sqrt(5))/2, number) / Math.sqrt(5));
				if ()

			}
			while (limit);
		}
		else
			System.out.println("Not a valid number.");

Am I going about this the right way? Not sure how to go about the if statement portion, but I believe it's needed. Any advice would be much appreciated. I've only been using Java for a few months now.

v/r

OneStepForward

What I have tried:

So far I've worked on the outer portion of the application. I need some guidance on the meat of it all.

Posted 13-Oct-16 5:42am

OneStepForward

Updated 13-Oct-16 15:49pm

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Comments

Richard Deeming 13-Oct-16 12:07pm

Why have you got a loop in there at all? According to Wikipedia[^], you've already calculated the result in a single line:

Fibnumber = Math.round(Math.pow((1 + Math.sqrt(5)) / 2, number) / Math.sqrt(5));

All you need to do is move that line inside an if (number >= 1 && number <= 46) { ... } block, and output the result.

OneStepForward 13-Oct-16 16:34pm

Based on modifiers for this assignment:

If the user enters a number above 2, then you will need to compute the vale nth Fibonacci number by using a loop.

Richard Deeming 13-Oct-16 16:50pm

OK, that means you're being too clever for the assignment! :)

Rather than using the rounding method and powers of the golden ratio, the assignment is expecting you to calculate the sequence using a for loop, adding the previous two numbers together at each step.

It's not as efficient as your current calculation, but I guess it's testing how well you understand loops, rather than how good your maths is. :)

Richard MacCutchan 13-Oct-16 12:08pm

Fibonacci is a sequence of integers: 1, 1, 2, 3, 5, 8 ... so why do you need those suffixes? Perhaps you could explain exactly what output you are trying to create.

Richard Deeming 13-Oct-16 12:29pm

I guess the suffix is on the ordinal, not the result.

The 6th number ... rather than ... is 8th.

OneStepForward 13-Oct-16 16:02pm

It's required via an assignment

Suvendu Shekhar Giri 13-Oct-16 12:31pm

Not sure what exactly are you asking.
Does the program throwing any error? You have an incomplete

if()

statement

OneStepForward 13-Oct-16 16:07pm

I'm trying to figure out how to proceed from here to get the output example I provided. I know something goes in the if statement related to a number ending 2 for nd, 3 for rd, etc.

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Patrice T · Answer 1 · 2016-10-13T15:49:00

This formula is certainly clever to get the answer in 1 go:

Java

Fibnumber = Math.round(Math.pow((1+Math.sqrt(5))/2, number) / Math.sqrt(5));

but power, square root and division on floating point are all eating a lot of cpu clock cycles, it may prove more economical to compute each value of the sequence because the next value only require an integer addition.

Executing your code step by step may help you to understand what the code is doing and what is missing.

You should learn to use the debugger as soon as possible. Rather than guessing what your code is doing, It is time to see your code executing and ensuring that it does what you expect.

The debugger allow you to follow the execution line by line, inspect variables and you will see that there is a point where it stop doing what you expect.
Debugger - Wikipedia, the free encyclopedia[^]
Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
http://docs.oracle.com/javase/7/docs/technotes/tools/windows/jdb.html[^]
https://www.jetbrains.com/idea/help/debugging-your-first-java-application.html[^]

The debugger is here to show you what your code is doing and your task is to compare with what it should do.

Advice: build some functions for each part of the problem, it help to handle changes without breaking other things.

Need help working with the fibonacci sequence in java

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