diff options
| -rw-r--r-- | csharp.html.markdown | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/csharp.html.markdown b/csharp.html.markdown index bb36d6ce..16e3749e 100644 --- a/csharp.html.markdown +++ b/csharp.html.markdown @@ -107,7 +107,8 @@ namespace Learning // Char - A single 16-bit Unicode character char fooChar = 'A'; - // Strings + // Strings -- unlike the previous base types which are all value types, + // a string is a reference type. That is, you can set it to null string fooString = "My string is here!"; Console.WriteLine(fooString); @@ -142,14 +143,21 @@ namespace Learning const int HOURS_I_WORK_PER_WEEK = 9001; // Nullable types - // any type can be made nullable by suffixing a ? + // any value type (i.e. not a class) can be made nullable by suffixing a ? // <type>? <var name> = <value> int? nullable = null; Console.WriteLine("Nullable variable: " + nullable); - // In order to use nullable's value, you have to use Value property or to explicitly cast it - string? nullableString = "not null"; - Console.WriteLine("Nullable value is: " + nullableString.Value + " or: " + (string) nullableString ); + // In order to use nullable's value, you have to use Value property + // or to explicitly cast it + DateTime? nullableDate = null; + // The previous line would not have compiled without the '?' + // because DateTime is a value type + // <type>? is equivalent to writing Nullable<type> + Nullable<DateTime> otherNullableDate = nullableDate; + + nullableDate = DateTime.Now; + Console.WriteLine("Nullable value is: " + nullableDate.Value + " or: " + (DateTime) nullableDate ); // ?? is syntactic sugar for specifying default value // in case variable is null |