Free mag vol1 | Page 165

CHAPTER 3  CORE C# PROGRAMMING CONSTRUCTS, PART I // The following string is printed verbatim, // thus all escape characters are displayed. Console.WriteLine(@"C:\MyApp\bin\Debug"); Also note that verbatim strings can be used to preserve white space for strings that flow over multiple lines. // White space is preserved with verbatim strings. string myLongString = @"This is a very very very long string"; Console.WriteLine(myLongString); Using verbatim strings, you can also directly insert a double quote into a literal string by doubling the " token. Console.WriteLine(@"Cerebus said ""Darrr! Pret-ty sun-sets"""); Strings and Equality As fully explained in Chapter 4, a reference type is an object allocated on the garbage-collected managed heap. By default, when you perform a test for equality on reference types (via the C# == and != operators), you will be returned true if the references are pointing to the same object in memory. However, even though the string data type is indeed a reference type, the equality operators have been redefined to compare the values of string objects, not the object in memory to which they refer. static void StringEquality() { Console.WriteLine("=> String equality:"); string s1 = "Hello!"; string s2 = "Yo!"; Console.WriteLine("s1 = {0}", s1); Console.WriteLine("s2 = {0}", s2); Console.WriteLine(); // Test these strings for equality. Console.WriteLine("s1 == s2: {0}", s1 == s2); Console.WriteLine("s1 == Hello!: {0}", s1 == "Hello!"); Console.WriteLine("s1 == HELLO!: {0}", s1 == "HELLO!"); Console.WriteLine("s1 == hello!: {0}", s1 == "hello!"); Console.WriteLine("s1.Equals(s2): {0}", s1.Equals(s2)); Console.WriteLine("Yo.Equals(s2): {0}", "Yo!".Equals(s2)); Console.WriteLine(); } The C# equality operators perform a case-sensitive, character-by-character equality test on string objects. Therefore, "Hello!" is not equal to "HELLO!", which is also different from "hello!". Also, keeping the connection between string and System.String in mind, notice that we are able to test for equality using the Equals() method of String as well as the baked-in equality operators. Finally, given that every string literal (such as "Yo") is a valid System.String instance, we are able to access string-centric functionality from a fixed sequence of characters. 99