private static void enums() { //enums are handy when we have a list of values and we want to pick one from it //enums are types (we can declare variables, properties, parameters, return values and so on) ConsoleColor oldColor = Console.ForegroundColor; //they are value types: //we copied the value of ForegroundColor into oldColor but if we change one of the two, the other remains unchanged Console.ForegroundColor = ConsoleColor.Red; System.Console.WriteLine("I'M SEEING RED!"); System.Console.WriteLine(oldColor); //still gray //we can only assign values picked up from the list, not simple strings or numbers //Console.ForegroundColor = "Red"; //does not compile //Console.ForegroundColor = 255; //does not compile Console.ForegroundColor = ConsoleColor.Cyan; //compiles Console.ForegroundColor = oldColor; //we can also define our own enums and use them //(you can find the definition in the file Enumerations.cs) ItalianDays favoriteDay = ItalianDays.Sabato; System.Console.WriteLine(favoriteDay); //Sabato }
private static void M01() { //type name; //name = expression; //type name = expression; //value types ==> struct, enum //reference types ==> class, arrays, delegates int a = 5; //inline memory //a = null; string s1 = null; //Nullable<int> a2 = 5; long l = long.MaxValue; a = (int)l; //bool b = (bool)a; //bool b = 1; a = 3; a = 5; int b = 10; b = a++; b = ++a; b = a > 5 ? 10 : 20; char c1 = 'a'; //c1 = "c"; //string s1 = 'asdg'; s1 = "asdg"; // s1 = s1 + "aa"; //asdgaa StringBuilder builder = new StringBuilder(); builder.Append("aa"); builder.Append("aa"); builder.Append("aa"); string s2 = builder.ToString(); s2.Trim(); s1 = a.ToString(); s1 = "5"; if (int.TryParse(s1, out a)) { } //enum Method02(); Point p = new Point(3, 4); Console.BackgroundColor = ConsoleColor.Yellow; ItalianDays day = ItalianDays.Lunedi; ItalianDays day2 = day; day = ItalianDays.Martedi; int d = (int)day; Console.WriteLine(day); Person simo = new Person(1, "Simo", "Cola"); simo.Id = 5; simo.Name = "Simona"; simo.Surname = "Colapicchioni"; simo.FavoriteDay = ItalianDays.Mercoledi; simo.DoSomething(); Console.WriteLine("What's the id?"); simo.Id = int.Parse(Console.ReadLine()); }