Program.cs

using System;
using System.Text;
using System.Collections.Generic;

namespace Matrix_Calculator
{
    class Program
    {
        static int ChoosenOne = 0;
        static short MenuPosition = 0;
        static int ChoosenOperation = 0;
        static string MenuName = "";
        static List<string> MenuInfo = new List<string>();
        static bool TraceM()
        {
            return false;
        }
        static List<string> MainMenu()
        {
            List<string> MainMenuInfo = new List<string>();

            MainMenuInfo.Add("Find trace matrix.");
            MainMenuInfo.Add("Find transpose matrix.");
            MainMenuInfo.Add("Find sum of two matrices.");
            MainMenuInfo.Add("Find difference of two matrices.");
            MainMenuInfo.Add("Find product of the two matrices.");
            MainMenuInfo.Add("Find product of the matrix on number. ");
            MainMenuInfo.Add("Find determinant of the matrix.");
            return MainMenuInfo;
        }
        static List<string> MethodMenu()
        {
            List<string> MethodMenuInfo = new List<string>();

            MethodMenuInfo.Add("Use text file");
            MethodMenuInfo.Add("Use console input");
            MethodMenuInfo.Add("Randomize");
            return MethodMenuInfo;
        }
        static void InputMethod(int ChoosenOperation)
        {
            switch (ChoosenOperation)
            {
                case (0):
                    InputPath();
                    break;
                case (1):
                    InputMatrix();
                    break;
                case (2):
                    RandomMatrix();
                    break;
                default:
                    break;
            }
        }
        static void InputPath()
        {
            Console.WriteLine("Plz, input correct path to your file with matrix(ces)");
            MenuInfo = new List<string>();
        }
        static void InputMatrix()
        {
            Console.WriteLine("Plz, input correct matrix(ces)");
            MenuInfo = new List<string>();
        }
        static void RandomMatrix()
        {
            Console.WriteLine("Plz, input correct size of matrix");
            MenuInfo = new List<string>();
        }
        static bool CheckMatrix()
        {
            return false;
        }
        static short PositionClear(short Position)
        {
            if (Position < 0)
                return 0;
            if (Position >= 2)
                return 2;
            return Position;
        }


        public static void PrintOutUpAndDown(List<string> InputList, int ChoosenOne)
        {
            // The loop that goes through all of the menu items.
            for (int i = 0; i < InputList.Count; i++)
            {
                // Print all output;
                if (i == ChoosenOne)
                {
                    // HighLight the choosen one.
                    Console.BackgroundColor = ConsoleColor.Gray;
                    Console.ForegroundColor = ConsoleColor.Black;
                    Console.WriteLine($">>{InputList[i]}");
                    Console.ResetColor();
                }
                else
                {
                    Console.WriteLine($"  {InputList[i]}");
                }
            }
        }
        static void Main(string[] args)
        {

            do
            {
                MenuPosition = PositionClear(MenuPosition);
                Console.Clear();
                if (MenuPosition == 0)
                {
                    Console.WriteLine("Main Menu");

                    MenuInfo = MainMenu();

                }
                if (MenuPosition == 1)
                {
                    Console.WriteLine(MenuName);
                    MenuInfo = MethodMenu();
                }
                if (MenuPosition == 2)
                {
                    InputMethod(ChoosenOperation);
                }

                PrintOutUpAndDown(MenuInfo, ChoosenOne);
                ConsoleKeyInfo key = Console.ReadKey(true);

                // Simple switch, if uparrow then decrease, downarrow then increase.
                switch (key.Key)
                {
                    case (ConsoleKey.UpArrow):
                        // Move cursor up.
                        if (ChoosenOne == 0)
                            ChoosenOne = MenuInfo.Count - 1;
                        else
                            ChoosenOne--;
                        break;
                    case (ConsoleKey.DownArrow):
                        // Move cursor down.
                        if (ChoosenOne == MenuInfo.Count - 1)
                            ChoosenOne = 0;
                        else
                            ChoosenOne++;
                        break;
                    case (ConsoleKey.RightArrow):
                        if (MenuPosition < 2)
                        {
                            MenuPosition += 1;
                            MenuName = MenuInfo[ChoosenOne];
                            ChoosenOperation = ChoosenOne;
                            ChoosenOne = 0;
                        }
                        break;
                    case (ConsoleKey.LeftArrow):
                        MenuPosition -= 1;
                        ChoosenOne = 0;
                        break;
                }
            } while (true);
        }
    }
}