Better way to sort array in descending order

Question

I have a array of int which I have to sort by descending.

Since I did not find any method to sort the array in descending order.Currently I am sorting the array in descending order as below

int[] array = new int[] { 3, 1, 4, 5, 2 };
Array.Sort<int>( array );
Array.Reverse( array );

Now,the question is that.Is there any better way to do the same in c#?

Answer 1

Use LINQ OrderByDescending method. It returns IOrderedIEnumerable<int> , which you can convert back to Array if you need so. Generally, List<> s are more functional then Array s.

array = array.OrderByDescending(c => c).ToArray();

Answer 2

Depending on the sort order, you can do this :

    int[] array = new int[] { 3, 1, 4, 5, 2 };
    Array.Sort<int>(array,
                    new Comparison<int>(
                            (i1, i2) => i2.CompareTo(i1)
                    ));

... or this :

    int[] array = new int[] { 3, 1, 4, 5, 2 };
    Array.Sort<int>(array,
                    new Comparison<int>(
                            (i1, i2) => i1.CompareTo(i2)
                    ));

i1 and i2 are just reversed.

Answer 3

Sure, You can customize the sort.

You need to give the Sort() a delegate to a comparison method which it will use to sort.

Using an anonymous method:

Array.Sort<int>( array,
delegate(int a, int b)
  {
    return b - a; //Normal compare is a-b
  }); 

Read more about it:

Sorting arrays
MSDN - Array.Sort Method (T[], Comparison)

Answer 4

For in-place sorting in descending order:

int[] numbers = { 1, 2, 3 };
Array.Sort(numbers, (a, b) => b.CompareTo(a));

For out-of-place sorting (no changes to input array):

int[] numbers = { 1, 2, 3 };
var sortedNumbers = numbers.OrderByDescending(x => x).ToArray();

Answer 5

Yes, you can pass predicate to sort. That would be your reverse implementation.

Answer 6

You may specify a comparer(IComparer implementation) as a parameter in Array.Sort, the order of sorting actually depends on comparer. The default comparer is used in ascending sorting

Answer 7

class Program
{
    private static int[] table;

    static void Main(string[] args)
    {
        int[] ints = new int[] { 6, 2, 5, 99, 55 };

       table = ints.OrderByDescending(x => x).ToArray();

        foreach (var item in table)
        {
            Console.WriteLine(item);
        }

    }