Lexicon

using System;
using System.Collections.Generic;
using System.IO;

namespace Lexicon
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<string, string> words = LoadDictionaryFromFile("words.txt");
            MainMenu(words);
        }

        static void MainMenu(Dictionary<string, string> words)
        {
            bool work = true;
            while (work)
            {
                Console.Clear();
                Console.WriteLine("Введите команду: " +
                    "\n1. Толкование слова" +
                    "\n2. Вывести все слова" +
                    "\n3. Вывести все слова с толкованием" +
                    "\n4. Выход");

                switch (Console.ReadLine())
                {
                    case "1":
                        Console.Write("\nВведите слово без пробелов: ");
                        if (TrySearchWord(words, Console.ReadLine(), out string result))
                        {
                            Console.WriteLine("\n" + result);
                        }
                        else
                        {
                            Console.WriteLine("Такого слова не найдено");
                        }
                        break;
                    case "2":
                        foreach (string word in OutputAllWords(words))
                        {
                            Console.WriteLine(word);
                        }
                        break;
                    case "3":
                        List<string> allWords = OutputAllThesaurus(words);
                        foreach (string word in allWords)
                        {
                            Console.WriteLine(word);
                        }
                        break;
                    case "4":
                        Console.WriteLine("Спасибо, что воспользовались нашим словарем!");
                        work = false;
                        break;
                    default:
                        Console.WriteLine("Такой команды не существует!");
                        break;
                }

                Console.ReadKey();
            }
        }

        static List<string> OutputAllWords(Dictionary<string, string> words)
        {
            List<string> outputWords = new List<string>();
            foreach (string word in words.Keys)
            {
                outputWords.Add(word);
            }
            return outputWords;
        }

        static List<string> OutputAllThesaurus(Dictionary<string, string> words)
        {
            List<string> output = new List<string>();
            foreach (var word in words)
            {
                output.Add(word.Key + "-" + word.Value);
            }
            return output;
        }

        static bool TrySearchWord(Dictionary<string, string> words, string word, out string result)
        {
            if (words.ContainsKey(word + " "))
            {
                result = word + " -" + words[word + " "];
                return true;
            }

            result = "";
            return false;
        }

        static Dictionary<string, string> LoadDictionaryFromFile(string fileName)
        {
            Dictionary<string, string> words = new Dictionary<string, string>();
            string[] file = File.ReadAllLines(fileName);
            foreach (string line in file)
            {
                string[] word = line.Split(new char[] { '-' });
                words.Add(word[0].ToLower(), word[1].ToLower());
            }

            return words;
        }
    }
}