Index 5 out of bounds for length at Simple_Inversions.main(Simple_Inversions.java:24)

Question

-The main function of my programm is counting the inversion of an array. Examples:

1. input: 5 0 1 2 3 4 (first input is the length of the array) output: 0 (because all numbers are in the right order)
2. input: 5 4 3 2 1 0 output: 4
3. input: 5 0 1 2 4 3 output: 1

-The first part of the code is defining the length of the array and filling the array with numbers. I feel I did everything right but I can't figure out why I get the following error:

"Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 5 out of bounds for length 5 at Simple_Inversions.main(Simple_Inversions.java:24)"

Hope you can help me. Thanks!

(Side note: The number 5 in the error is 5 because the length of the array I enterd was 5. So it changes depending on that)

import java.util.Scanner;

public class Simple_Inversions {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int index;
        int anzahl;
        int[] feld;
        int inversionen;

        anzahl = sc.nextInt();
        feld = new int[anzahl];

        index = 0;
        while ( index < anzahl )
        {
            feld[index] = sc.nextInt();
            index = index + 1;
        }
          inversionen=0;
        index=0;
        while(index < feld.length){
            if(feld[index+1]<feld[index]) {

                inversionen = inversionen + 1;
            }
            index=index+1;


        }



        System.out.println(inversionen);


    }
}

Answer 1

It is failing at if(feld[index+1]<feld[index]) when index is 4, this line tries to access 5th element, as suggested by @zhh

Change while(index < feld.length) to while ((index + 1) < feld.length)