c sharp programming

String order comparison



String’s CompareTo instance method performs culture-sensitive, case-sensitive order
comparison. Unlike the == operator, CompareTo does not use ordinal comparison: for
ordering, a culture-sensitive algorithm is much more useful.
Here’s the method’s definition:
public int CompareTo (string strB);
The  CompareTo  instance  method  implements  the  generic
IComparable  interface,  a  standard  comparison  protocol  used
across  the  .NET  Framework. This means  string’s  CompareTo
defines the default ordering behavior strings,  in such applica-
tions as sorted collections, for instance. For more information


For other kinds of comparison, you can call the static Compare and CompareOrdinal
methods:
public static int Compare (string strA, string strB,
                           StringComparison comparisonType);
public static int Compare (string strA, string strB, bool ignoreCase,
                           CultureInfo culture);
public static int Compare (string strA, string strB, bool ignoreCase);
public static int CompareOrdinal (string strA, string strB);
The last two methods are simply shortcuts for calling the first two methods.
All of the order comparison methods return a positive number, a negative number,
or zero, depending on whether the first value comes after, before, or alongside the
second value:
Console.WriteLine ("Boston".CompareTo ("Austin"));    // 1
Console.WriteLine ("Boston".CompareTo ("Boston"));    // 0
Console.WriteLine ("Boston".CompareTo ("Chicago"));   // -1
Console.WriteLine ("?".CompareTo ("u"));              // 0
Console.WriteLine ("foo".CompareTo ("FOO"));          // -1


The following performs a case-insensitive comparison using the current culture:
Console.WriteLine (string.Compare ("foo", "FOO", true));   // 0
By supplying a CultureInfo object, you can plug in any alphabet:
// CultureInfo is defined in the System.Globalization namespace
CultureInfo german = CultureInfo.GetCultureInfo ("de-DE");
int i = string.Compare ("Müller", "Muller", false, german);