01. problem Final exam 13 dec 2020

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



class Program
{

    static void Main()
    {
        var input = Console.ReadLine();

        string command = Console.ReadLine();

        while (command != "End")
        {
            string[] line = command.Split();
            string cmd = line[0];

            if (cmd == "Translate")
            {
                var oldChar = line[1];
                var newChar = line[2];

                input = input.Replace(oldChar, newChar);
                Console.WriteLine(input);
            }
            else if (cmd == "Includes")
            {
                string isContains = line[1];

                if (input.Contains(isContains))
                {
                    Console.WriteLine("True");
                }
                else
                {
                    Console.WriteLine("False");
                }
            }
            else if (cmd == "Lowercase")
            {
                input = input.ToLower();

                Console.WriteLine(input);
            }
            else if (cmd == "FindIndex")
            {
                var index = line[1];
                int indexOf = input.LastIndexOf(index);
                Console.WriteLine(indexOf);
            }
            else if (cmd == "Start")
            {
                StringBuilder sb = new StringBuilder();
                string isSame = line[1];

                bool isTrue = true;

                while (isTrue)
                {
                    for (int i = 0; i < input.Length; i++)
                    {
                        var diff = input[i].ToString();
                        if(diff == " ")
                        {
                            isTrue = false;
                            break;
                        }
                        else if(diff != " ")
                        {
                            sb.Append(diff);
                        }
                    }
                }

               if(isSame == sb.ToString())
                {
                    Console.WriteLine("True");
                }
                else
                {
                    Console.WriteLine("False");
                }
            }
            else if (cmd == "Remove")
            {
                int startIndex = int.Parse(line[1]);
                int endIndex = int.Parse(line[2]);


                input = input.Remove(startIndex, endIndex);

                Console.WriteLine(input);
            }


            command = Console.ReadLine();
        }
    }
}