Remove zero's (empty spaces) from arrays-CodePudding

I've written a console application (.NET 5.0) in C# in Visual Studio which prints out all the even and odd numbers you give as input.

It works as intended but there is a problem that I will encounter in the future when making similar applications.

Whenever a number isn't odd the respective place of that array (Number_odd) will have a zero added to it. How do I stop that from happening? I currently filtered out all the zero's by not printing any zero.

The output currently looks like "odd: 5 9 7 1 3" with all the zero's filtered. Without filtering the output looks like "odd: 0 5 9 7 1 3 0 0 0"

If I (for instance) say that "0" is an odd number I cannot print it because it gets filtered. How do I fix that?

using System;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] numbers = Array.ConvertAll(Console.ReadLine().Split(" "), Convert.ToInt32);
            int uitkomst = 0;
            int[] numbers_odd = new int[numbers.Length];
            int[] numbers_even = new int[numbers.Length];

            for (int repeat = 0; repeat < numbers.Length; repeat  )
            {
                uitkomst = numbers[repeat] % 2;
                //Console.WriteLine(uitkomst);

                if(uitkomst == 1) // ODD
                {
                    numbers_odd[repeat] = numbers[repeat];
                    //Console.WriteLine(numbers_odd[repeat]);
                }

                if (uitkomst == 0) // Even
                {
                    numbers_even[repeat] = numbers[repeat];
                    //Console.WriteLine(numbers_even[repeat]);
                }
            }

            Console.Write("even: ");
            foreach (int item in numbers_even)
            {
                if(item == 0)
                {

                }
                else
                {
                    Console.Write(item   " ");
                }
            }
            Console.WriteLine(" ");

            Console.Write("odd: ");
            foreach (int item in numbers_odd)
            {
                if (item == 0)
                {

                }
                else
                {
                    Console.Write(item   " ");
                }
            }

        }
    }
}

CodePudding user response：

Make these two lines

int[] numbers_odd = new int[numbers.Length];
int[] numbers_even = new int[numbers.Length];

use List<int> instead

var numbers_odd = new List<int>();
var numbers_even = new List<int>();

and then Add values to the correct one

if(uitkomst == 1) // ODD
{
    numbers_odd.Add(numbers[repeat]);
    //Console.WriteLine(numbers_odd[repeat]);
 }

 if (uitkomst == 0) // Even
 {
     numbers_even.Add(numbers[repeat]);
     //Console.WriteLine(numbers_even[repeat]);
 }

Now your lists only contain the odd or even numbers and no zeros

Console.Write("even: ");
foreach (int item in numbers_even)
{
     Console.Write(item   " ");
}

CodePudding user response：

It isn't that a zero is being added; an array is a fixed size, and is initialized with all default values - zero in this case. You then loop over numbers.Length and only write to one of the two arrays - leaving the other array zero at that position.

Perhaps consider using a list instead of an array for the two parts, and .Add(...) as you choose.

CodePudding user response：

The answer posted is already a good solution. Just wanted to add that, If you are learning C# and working with collections (arrays, lists etc.) consider Linq as one of useful tools.

Here is how you can leverage them in your example.

var numbers = Array.ConvertAll(Console.ReadLine().Split(" "), Convert.ToInt32);

var numbers_odd = numbers.Where(n => (n % 2)==1);

var numbers_even = numbers.Where(n =>(n % 2) == 0);