import javax.swing.JOptionPane;

public class Fibonacci
{
  public static void main (String[]args)
  {
    int[] fibonacci;  //This is the array that will contain the Fibonacci numbers
    String input;     //This contains the input from the JOptionPane
    int inputNum;     //This is the parsed number from the input String.
    int output = 0;   //This is the output to be printed to the console.

    //This will generate and show the input dialog box to take in the Fibonacci number that you want to display.
    input = JOptionPane.showInputDialog ("Please enter the Fibonacci number you want to calculate:");
    inputNum = Integer.parseInt(input);

    //Check the inputNum and depending on the starting value...
    if (inputNum == 1)
      output = 0;
    else if (inputNum == 2)
      output = 1;
    else if (inputNum > 2)
    {
      //This initilizes the fibonacci array and sets the starting values.
      fibonacci = new int[inputNum];
      fibonacci[0] = 0;
      fibonacci[1] = 1;

      //You start this loop at 2 because you have already calculated the starting two values and you want to start on the third index of the array.
      for (int i = 2; i < inputNum; i++)
        fibonacci[i] = fibonacci[i-1] + fibonacci[i-2];

      output = fibonacci[inputNum - 1];
    }

    System.out.println ("The number is: " + output);
  }
}