Difference between revisions of "Fibonacci sequence"

Revision as of 23:29, 1 April 2010

{{1010PrAD

|ProblemName=Fibonacci sequence

|Problem=Write a complete Java program Fibonacci that:

• prompts the user to enter an input n and cast it to integer
  
• get the nth fibonacci numbers using FOR loop, based on the user's input
  
• prints out the nth fibonacci number, using JOptionPane.showMessageDialog method.
  

Note that the fibonacci sequence is F(0) = 1, F(1) = 1, F(n) = F(n-1) + F(n-2) for n > 1.
Example: F(5) = 1, 1, 2, 3, 5, 8
Your output should look something like
"The 5th number of the fibonacci sequence is 5."

You may assume that the user always enters correct intenger format.

import javax.swing.JOptionPane;

public class Fibonacci
{
    public static void main(String[] args)
    {     	
 		int current = 1;
 		int previous = 0;

		int n = Integer.parseInt(JOptionPane.showInputDialog("Please enter n"));

 		for(int i = 0; i < n; i++)
                {
 			int temp = previous;
 			previous = current;
 			current = temp + previous;
 		}
 		
 		JOptionPane.showMessageDialog(null, "The " + n + "th Fibonacci number is " + current);
    }
}

|SideSectionTitle=...by students

|SideSection=
Taken from http://www.flickr.com/photos/daniello/565304023/

An image or By Students section

 
In order to get the user input by JOptionPane, you will first have to import the swing package.
You can import swing package by 
import javax.swing.*; or import javax.swing.JOptionPane;

Then, the next step would be declaring variables; in this program we will need only two int variables.
current will be F(n) and previous will be F(n-1). Do NOT forget to declare them outside the for loop.
}}