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
– Alan, Commented Aug 3, 2018 at 6:48
What would be the reault of an empty array? How many elements can you sum up? — LuCio
– LuCio, Commented Aug 3, 2018 at 6:48
simplest: if (input == null) return new int[2]; some better, just do the for if (input != null) (Note: why do you need x?) — user85421
– user85421, Commented Aug 3, 2018 at 6:56

Henry · Accepted Answer · 2018-08-03 06:49:21Z

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 3, 2018 at 6:49

Henry

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3 Comments

LuCio Over a year ago

I'm not sure. I think the result has always to have two elements: the sum of even and the sum of odd elements.

Henry Over a year ago

@LuCio it will. x is just the input to the summing functionality.

LuCio Over a year ago

Ok ... i see ... it's not the result.

score 2 · Accepted Answer · 2018-08-03 07:04:19Z

2

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};
}

edited Aug 3, 2018 at 7:04

answered Aug 3, 2018 at 6:52

user2575725

Comments

Pantelis Bouboulis · Accepted Answer · 2018-08-03 07:07:06Z

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.

Gurankas · Accepted Answer · 2018-08-03 07:26:01Z

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 3, 2018 at 7:26

answered Aug 3, 2018 at 6:52

Gurankas

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2 Comments

Riddler Over a year ago

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.

Henry Over a year ago

Did you try to compile that? x[i] has type int so it is a primitive type, not a reference. It cannot be null.

user2903536 · Accepted Answer · 2019-11-05 04:35:07Z

0

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

answered Nov 5, 2019 at 4:35

user2903536

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Comments

Consti P · Accepted Answer · 2018-08-03 06:50:43Z

-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 3, 2018 at 6:50

Consti P

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