Empty integer array in java

Question

Write a function that takes an array as input and returns an array of 2 numbers. The returned array contains the sum of even numbers and sum of odd numbers from the input.

If any of the input is null it should be treated as an empty array

Example: Input:
[30, 18, 2, 83, 20, 71]
Output:
[70, 154]

Input:
[14, 11, 10, 67, 41]
Output:
[24, 119]

Input: [36, 24, -82, 29, 44, -3, -100, -5, 49] Output: [-78, 70]

The function that I have written is

public int[] getSumOfEvensAndOdds(int[] input) {
        
        int x[] = input;
        int even = 0, odd = 0;
        for (int i = 0; i < x.length; i++) {
            if (x[i] % 2 == 0)
                even += x[i];
            else
                odd += x[i];
        }
        int[] ans={even, odd};
        return ans;
    }

But how should I incorporate the part of the empty array?

What do you mean with "How should I incorporate the part of the empty array"? — Alan, Aug 03 '18 at 06:48
What would be the reault of an empty array? How many elements can you sum up? — LuCio, Aug 03 '18 at 06:48
simplest: `if (input == null) return new int[2];` some better, just do the `for` `if (input != null)` (Note: why do you need `x`?) — user85421, Aug 03 '18 at 06:56

score 4 · Answer 1 · answered Aug 03 '18 at 06:49

4

Check if input is null first. If it is, work on an empty array instead:

int x[] = input == null ? new int[0] : input;

answered Aug 03 '18 at 06:49

Henry

42,982
7
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I'm not sure. I think the result has always to have two elements: the sum of even and the sum of odd elements. – LuCio Aug 03 '18 at 06:50
@LuCio it will. `x` is just the input to the summing functionality. – Henry Aug 03 '18 at 06:51
Ok ... i see ... it's not the result. – LuCio Aug 03 '18 at 06:52

score 2 · Accepted Answer · 2018-08-03T07:04:19.547

if any of the input is null it should be treated as an empty array

Why not just check for null value?

public int[] getSumOfEvensAndOdds(int[] input) {
    int even = 0, odd = 0;
    if(null != input){
        for (int i: input) {
            if (0 == i % 2){
                even += i;
            } else{
                odd += i;
            }
        }
    }
    return new int[]{even, odd};
}

Gurankas · Answer 3 · 2018-08-03T07:26:01.390

0

public int[] getSumOfEvensAndOdds(int[] input) {

        int x[] = input;
        int even = 0, odd = 0;
        for (int i = 0; i < x.length; i++) {
        if(x[i] != null)    //in case array contains elements which aren't null
        {
            if (x[i] % 2 == 0)
                even += x[i];
            else
                odd += x[i];
        }
        else   //in case the array has null array elements
        {
           even = 0;
           odd = 0;
        }
        int[] ans={even, odd};
        return ans;
    }

edited Aug 03 '18 at 07:26

answered Aug 03 '18 at 06:52

Gurankas

229
4
16

Thank you for the response. As you have stated here while checking if the array is empty, but the question says that if any of the elements is null then treat it as an empty array. – Riddler Aug 03 '18 at 06:59
Did you try to compile that? `x[i]` has type `int` so it is a primitive type, not a reference. It cannot be `null`. – Henry Aug 03 '18 at 08:19

score 0 · Answer 4 · answered Aug 03 '18 at 07:07

You need something like this:

public class Test {

public static int[] getSumOfEvensAndOdds(int[] input) {
    int[]   def = {0,0};

    if (input != null && input.length!=0) {
        int x[] = input;
        int even = 0, odd = 0;
        for (int i = 0; i < x.length; i++) {
            if (x[i] % 2 == 0)
                even += x[i];
            else
                odd += x[i];
        }
        int[] ans = {even, odd};
        return ans;
    }

    return def;
}

public static void main(String [ ] args){
    int[]   ar = {10,20,30,40,50,60,71,80,90,91};
    int[]   res;

    res = getSumOfEvensAndOdds(ar);
    System.out.println("Result: " + res[0] + " " + res[1]);

    int[]   ar2 = {};
    res = getSumOfEvensAndOdds(ar2);
    System.out.println("Result: " + res[0] + " " + res[1]);

    int[]   ar3 = null;
    res = getSumOfEvensAndOdds(ar3);
    System.out.println("Result: " + res[0] + " " + res[1]);
}

}

I use input!=null to check whether the array is null and input.length!=0 to check if its size is 0. Also, in the main method I give three examples.

score 0 · Answer 5 · answered Nov 05 '19 at 04:35

0

Empty array may be return like this return new int[]{}

answered Nov 05 '19 at 04:35

user2903536

1,716
18
25

score -1 · Answer 6 · answered Aug 03 '18 at 06:50

-1

Your question is just about arrays being empty. A quick search got me this: How can I check whether an array is null / empty?

answered Aug 03 '18 at 06:50

Consti P

445
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Empty integer array in java

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