CODEWITHSUNDEEP
javaarrays
Adam Morton
Adam Morton

Reputation: 11

Array Outofbounds exception

im getting a out of bounds error on line 57. any help is appreciated. the program takes 1 integer and creates and array with that many indexes. it then asks for more integers to fill it up. it then takes all the even numbers and places it into a second array with is then outputted.

run:
Enter the ammount of integers you will require.
10
Enter your integers: 
1
Enter your integers: 
2
Enter your integers: 
3
Enter your integers: 
4
Enter your integers: 
5
Enter your integers: 
6
Enter your integers: 
7
Enter your integers: 
8
Enter your integers: 
9
Enter your integers: 
0
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
    at AllEven.arrcheck2(AllEven.java:57)
    at AllEven.main(AllEven.java:24)
Java Result: 1
BUILD SUCCESSFUL (total time: 4 seconds)

CODE

import java.util.*;

public class AllEven {

public static void main(String[] args) {
    int read;

    Scanner kybd = new Scanner(System.in);

    System.out.println("Enter the ammount of integers you will require.");

    read = kybd.nextInt();

    int[] arr1 = new int[read];
    int[] arr2;

    int count = 0;
    arrRead(arr1);
    arrcheck(arr1);

    arr2 = new int[count];

    arrcheck2(arr1, arr2);
    mainPrint(arr2);



}

public static int arrcheck(int[] arr1) {
    int count = 0;
    for (int i = 0; i < arr1.length; i++) {
        if (arr1[i] % 2 == 0) {
            count++;

        }

    }
    return count;
}

public static void arrRead(int[] arr1) {
    Scanner kybd = new Scanner(System.in);

    for (int i = 0; i < arr1.length; i++) {
        System.out.println("Enter your integers: ");
        arr1[i] = kybd.nextInt();

    }
}

public static void arrcheck2(int[] arr1, int[] arr2) {
    int j = 0;
    for (int i = 0; i < arr1.length; i++) {
        if (arr1[i] % 2 == 0) {
            arr2[j] = arr1[i];
            j++;

        }

    }

}

public static void mainPrint(int[] arr2) {
    for (int i = 0; i < arr2.length; i++) {
        System.out.println("Printing Even Numbers.");
        System.out.println(arr2[i]);
    }
}
}

ok so thanks everyone who helped, But now after the integers have been inputted the program just finishes without displaying anything after.

Upvotes: 1

Views: 172

Answers (8)

amphibient
amphibient

Reputation: 31222

You are not initializing your array int[] arr2. You should not use an array to populate even elements from the initial array because arrays require a determined size upon initialization -- you are better off using ArrayList and then conver it into an array once you know the definitive size, if you must.

Upvotes: 1

Rohit Jain
Rohit Jain

Reputation: 213223

You need to assign the return value of arrcheck invocation in count variable before creating arr2. Otherwise, you would create your arr2 with size 0.

Change: -

int count = 0;
arrRead(arr1);
arrcheck(arr1);

to: -

arrRead(arr1);
int count = arrcheck(arr1);

Upvotes: 2

Kevin DiTraglia
Kevin DiTraglia

Reputation: 26058

For starters you have your arrcheck function returning a count and not doing anything with it. I suspect you meant to write something like this:

arrRead(arr1);
int count = arrcheck(arr1);

otherwise your next line:

arr2 = new int[count];

creates an array of size 0 which will cause array out of bounds as soon as it is accessed.

Also you spelled Amount wrong, I think the rest of the program should work with the above change.

Upvotes: 1

JustinDanielson
JustinDanielson

Reputation: 3185

You need to initialize arr2 to the same length as arr1. int count = read will fix the issue. Or you can remove count entirely and just use read when initializing the array.

    read = kybd.nextInt();

    int[] arr1 = new int[read];
    int[] arr2;

    int count = read;
    arrRead(arr1);
    arrcheck(arr1);

    arr2 = new int[count];

Upvotes: 1

tim_a
tim_a

Reputation: 950

You create an array with length 0.

arr2 = new int[count];

You should give it a length bigger than 0. If you want it to be the same length as arr1 just do arr2 = new int[read];

Upvotes: 1

Itay Karo
Itay Karo

Reputation: 18286

The size of arr2 is 0. so when you try to access a non existing index in it you get the exception.

Upvotes: 1

Dan W
Dan W

Reputation: 5782

You are defining arr2 as a zero-length array:

int count = 0;
....
arr2 = new int[count];

Then, in arrcheck2 you have the line:

arr2[j] = arr1[i];

This will not work because arr2 has no length so you cannot put anything into it.

Upvotes: 1

rgamber
rgamber

Reputation: 5849

After brief look at the code I think your problem lies here:

int count = 0;
arrRead(arr1);
arrcheck(arr1);

arr2 = new int[count]; //array of size 0!

arrcheck2(arr1, arr2);

Upvotes: 1

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