static void Main(string[] args) { List <string> Command = new List <string>(); List <int> XList = new List <int>(); Console.ForegroundColor = ConsoleColor.Yellow; Console.WriteLine("Enter First polynomial number :"); Console.ForegroundColor = ConsoleColor.White; string Pol1 = Console.ReadLine(); Console.ForegroundColor = ConsoleColor.Yellow; Console.WriteLine("Enter Second polynomial number :"); Console.ForegroundColor = ConsoleColor.White; string Pol2 = Console.ReadLine(); Polynomial polymer = new Polynomial(Pol1, Pol2); // take command from user ; + for sum Console.ForegroundColor = ConsoleColor.Yellow; Console.WriteLine("Enter Commands : (+ for sum - for subtraction . to set X ; to finish"); Console.ForegroundColor = ConsoleColor.White; int com = 0; string commend; commend = Console.ReadLine(); Command.Add(commend); while (Command[com] != ";") { if (Command[com] == ".") { Console.ForegroundColor = ConsoleColor.Yellow; Console.Write("Enter X >> "); Console.ForegroundColor = ConsoleColor.White; int xvalue = int.Parse(Console.ReadLine()); XList.Add(xvalue); } commend = Console.ReadLine(); Command.Add(commend); com++; } int XIndex = 0; for (int i = 0; i < Command.Count; i++) { Console.ForegroundColor = ConsoleColor.Green; if (Command[i] == "+") { polymer.Sum(); } else if (Command[i] == "-") { polymer.Subtraction(); } else if (Command[i] == ".") { polymer.SetX(XList[XIndex]); XIndex++; } } Console.ForegroundColor = ConsoleColor.White; Console.Write("\n\n\n\n <<Finish>> -------------> Developed By :"); Console.ForegroundColor = ConsoleColor.Magenta; Console.Write(" <Aryana.Bkh>"); Console.ForegroundColor = ConsoleColor.White; Console.Write("\n\t\t\t My Github : "); Console.ForegroundColor = ConsoleColor.Magenta; Console.Write("https://github.com/AryanaBakhshandeh "); Console.ReadKey(); }