Array Modifier

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Problem_2.Array_Modifier
{
    class Program
    {
        static void Main(string[] args)
        {
            long[] numbers = Console.ReadLine().Split().Select(long.Parse).ToArray();
            string[] commands = Console.ReadLine().Split().ToArray();


            while (commands[0] != "end")
            {
                string command = commands[0];
                int index1 = 0;
                int index2 = 0;
                if (commands.Length > 1)
                {
                    index1 = int.Parse(commands[1]);
                    index2 = int.Parse(commands[2]);
                }
                if (command == "swap") swap(numbers, index1, index2);
                else if (command == "multiply") multiply(numbers, index1, index2);
                else if (command == "decrease") decrease(numbers);
                commands = Console.ReadLine().Split().ToArray();
            }

            Console.WriteLine(string.Join(", ", numbers));
        }

        private static void decrease(long[] numbers)
        {
            for (int num = 0; num < numbers.Length; num++)
            {
                numbers[num] = numbers[num] - 1;
            }
        }

        private static void multiply(long[] numbers, int index1, int index2)
        {
            long temp = numbers[index1] * numbers[index2];
            numbers[index1] = temp;
        }

        private static void swap(long[] numbers, int index1, int index2)
        {
            long temp1 = numbers[index1];
            long temp2 = numbers[index2];
            numbers[index1] = temp2;
            numbers[index2] = temp1;
        }
    }
}