Array.Sort<T> Method (T[], Int32, Int32)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Sorts the elements in a range of elements in an Array using the IComparable<T> generic interface implementation of each element of the Array.
Assembly: mscorlib (in mscorlib.dll)
Type Parameters
- T
The type of the elements of the array.
Parameters
- array
- Type:
T
[]
The one-dimensional, zero-based Array to sort
- index
- Type: System.Int32
The starting index of the range to sort.
- length
- Type: System.Int32
The number of elements in the range to sort.
| Exception | Condition |
|---|---|
| ArgumentNullException | array is null. |
| ArgumentOutOfRangeException | index is less than the lower bound of array. -or- length is less than zero. |
| ArgumentException | index and length do not specify a valid range in array. |
| InvalidOperationException | One or more elements in array do not implement the IComparable<T> generic interface. |
Each element within the specified range of elements in array must implement the IComparable<T> generic interface to be capable of comparisons with every other element in array.
If the sort is not successfully completed, the results are undefined.
This method uses the QuickSort algorithm. This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. In contrast, a stable sort preserves the order of elements that are equal.
On average, this method is an O(n log n) operation, where n is length; in the worst case it is an O(n ^ 2) operation.
The following code example demonstrates the Sort<T>(T[], Int32, Int32) generic method overload and the Sort<TKey, TValue>(TKey[], TValue[], Int32, Int32, IComparer<TKey>) generic method overload for sorting a range in an array.
The code example defines an alternative comparer for strings, named ReverseCompare, which implements the IComparer<string> (IComparer(Of String) in Visual Basic, IComparer<String^> in Visual C++) generic interface. The comparer calls the CompareTo(String) method, reversing the order of the comparands so that the strings sort high-to-low instead of low-to-high.
The code example creates and displays an array of dinosaur names, consisting of three herbivores followed by three carnivores (tyrannosaurids, to be precise). The Sort<T>(T[], Int32, Int32) generic method overload is used to sort the last three elements of the array, which is then displayed. The Sort<TKey, TValue>(TKey[], TValue[], Int32, Int32, IComparer<TKey>) generic method overload is used with ReverseCompare to sort the last three elements in reverse order. The thoroughly confused dinosaurs are displayed again.
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The calls to the Sort<T>(T[], IComparer<T>) and BinarySearch<T>(T[], T, IComparer<T>) generic methods do not look any different from calls to their nongeneric counterparts, because Visual Basic, C#, and C++ infer the type of the generic type parameter from the type of the first argument. |
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To run this example, see Building examples that have static TextBlock controls for Windows Phone 8. |
using System; using System.Collections.Generic; public class ReverseComparer : IComparer<string> { public int Compare(string x, string y) { // Compare y and x in reverse order. return y.CompareTo(x); } } public class Example { public static void Demo(System.Windows.Controls.TextBlock outputBlock) { string[] dinosaurs = {"Pachycephalosaurus", "Amargasaurus", "Mamenchisaurus", "Tarbosaurus", "Tyrannosaurus", "Albertasaurus"}; outputBlock.Text += "\n"; foreach (string dinosaur in dinosaurs) { outputBlock.Text += dinosaur + "\n"; } outputBlock.Text += String.Format("\nSort(dinosaurs, 3, 3)") + "\n"; Array.Sort(dinosaurs, 3, 3); outputBlock.Text += "\n"; foreach (string dinosaur in dinosaurs) { outputBlock.Text += dinosaur + "\n"; } ReverseComparer rc = new ReverseComparer(); outputBlock.Text += String.Format("\nSort(dinosaurs, 3, 3, rc)") + "\n"; Array.Sort(dinosaurs, 3, 3, rc); outputBlock.Text += "\n"; foreach (string dinosaur in dinosaurs) { outputBlock.Text += dinosaur + "\n"; } } } /* This code example produces the following output: Pachycephalosaurus Amargasaurus Mamenchisaurus Tarbosaurus Tyrannosaurus Albertasaurus Sort(dinosaurs, 3, 3) Pachycephalosaurus Amargasaurus Mamenchisaurus Albertasaurus Tarbosaurus Tyrannosaurus Sort(dinosaurs, 3, 3, rc) Pachycephalosaurus Amargasaurus Mamenchisaurus Tyrannosaurus Tarbosaurus Albertasaurus */
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