02. Array Modifier

using System;
using System.Linq;


namespace _02_Mid_Exam_Tasks
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] num = Console.ReadLine()
                .Split()
                .Select(int.Parse)
                .ToArray();



            for (int i = 0; i < num.Length; i++)
            {

                string[] arr = Console.ReadLine().Split();

                string command = arr[0];


                switch (command)
                {
                    case "swap":
                        int index1 = int.Parse(arr[1]);
                        int index2 = int.Parse(arr[2]);
                        int temp = num[index1];

                        num[index1] = num[index2];
                        num[index2] = temp;

                        break;
                    case "multiply":
                        int indexOne = int.Parse(arr[1]);
                        int indexTwo = int.Parse(arr[2]);

                        num[indexOne] = num[indexOne] * num[indexTwo];

                        break;
                    case "decrease":
                        for (int j = 0; j < num.Length; j++)
                        {
                            num[j] = num[j] - 1;
                        }
                        break;
                    case "end":
                        break;
                }
            }
            Console.WriteLine(string.Join(", ", num));
        }
    }
}