Learning C# 3.0

Sorting Arrays

Two useful static methods from Table 10-1 that deserve a closer look are Sort( ) and Reverse( ). These methods do what you think they would: Reverse( ) reverses the order of elements in the array, and Sort( ) sorts the elements in order. These two methods are fully supported for arrays of the built-in C# types, such as string, so sorting an array of strings puts the elements in alphabetical order, and sorting an array of ints puts them in numeric order. Making the Sort( ) method work with your own classes is a bit trickier, because you must implement the IComparable interface (see Chapter 13 for more on interfaces). Example 10-8 demonstrates the use of these two methods to manipulate String objects.

Example 10-8. Array.Sort and Array.Reverse are static methods that let you sort and reverse the contents of an array

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Example_10_8_ _ _ _Sorting_and_Reversing_Arrays
{
    public class Tester
    {
        public static void PrintMyArray(string[] theArray)
        {

            foreach (string str in theArray)
            {
                Console.WriteLine("Value: {0}", str);
            }
            Console.WriteLine("\n");

        }

        static void Main( )
        {

            String[] myArray =
            {
                "Proust", "Faulkner", "Mann", "Hugo"
            };

            PrintMyArray(myArray);
            Array.Reverse(myArray);
            PrintMyArray(myArray);

            String[] myOtherArray =
            {
                "We", "Hold", "These", "Truths", 
                "To", "Be", "Self", "Evident",
            };

            PrintMyArray(myOtherArray);
            Array.Sort(myOtherArray);
            PrintMyArray(myOtherArray);

        }
    }
}

The output ...