Fibonacci - Java Sample Program

//*************************************************************
// Program: nth Fibonacci number
// Given the first two numbers of a Fibonacci sequence, this
// determines and outputs the desired number of the Fibonacci
// sequence.
// Filename: FibonacciNumber.java
//*************************************************************

import javax.swing.JOptionPane;
public class FibonacciNumber
{
public static void main (String[] args)
{
//Declare variables
String inputString;
String outputString;
int previous1;
int previous2;
int current = 0;
int counter;
int nthFibonacci;

inputString =JOptionPane.showInputDialog("Enter the first "
+ "Fibonacci number: "); //Step 1
previous1 = Integer.parseInt(inputString); //Step 2
inputString = JOptionPane.showInputDialog("Enter the second "
+ "Fibonacci number: "); //Step 3
previous2 = Integer.parseInt(inputString); //Step 4

outputString = "The first two numbers of the "
+ "Fibonacci sequence are: "
+ previous1 + " and " + previous2; //Step 5

inputString =JOptionPane.showInputDialog("Enter the position "
+ "of the desired number in "
+ "the Fibonacci sequence: "); //Step 6

nthFibonacci = Integer.parseInt(inputString); //Step 7

if (nthFibonacci == 1) //Step 8.a
current = previous1;
else if (nthFibonacci == 2) //Step 8.b
current = previous2;
else //Step 8.c
{
counter = 3; //Step 8.c.1
//Steps 8.c.2 - 8.c.5
while (counter <= nthFibonacci)
{
current = previous2 + previous1; //Step 8.c.2
previous1 = previous2; //Step 8.c.3
counter++; //Step 8.c.5
}
}

outputString ¼ outputString + "\nThe "
+ nthFibonacci
+ "th Fibonacci number of "
+ "the sequence is: "
+ current; //Step 9

JOptionPane.showMessageDialog(null, outputString,"Fibonacci Number",
JOptionPane.INFORMATION_MESSAGE); //Step 10
System.exit(0);
}
}

//Sample Output: