06. Even and Odd Subtraction

using System;
using System.Linq;

namespace SumEvenNumbers
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] num = Console.ReadLine()
                .Split()
                .Select(int.Parse)
                .ToArray();
            int sumEven = 0;
            int sumOdd = 0;

            for (int i = 0; i < num.Length; i++)
            {
                int current = num[i];
                if (current % 2 == 0)
                {
                    sumEven += current;
                }
                else
                {
                    sumOdd += current;
                }
            }
            Console.WriteLine(sumEven - sumOdd);
        }
    }
}

Решение с LINQ:

using System;
using System.Linq;

namespace SumEvenNumbers
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] numbers = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int sumEven = numbers.Where(a => a % 2 == 0).Sum();
            int sumOdd = numbers.Where(a => a % 2 == 1).Sum();

            Console.WriteLine(sumEven - sumOdd);
        }
    }
}