How to Sort an Array in C# using Array.Sort()

Sorting is the process of arranging data in a specific order, typically ascending or descending. It helps in organizing data, making it easier to search, analyze, and process efficiently. In C#, arrays can be sorted using the Array.Sort() method.

• This method is used to sort elements of a one-dimensional array and provides multiple overloaded methods.
• It handles different sorting scenarios such as default sorting, custom comparison, and sorting a specific range of elements.

In this article, we will focus on the most commonly used overloads of the Array.Sort() method.

1. Sort<T>(T[]) Method

This method sorts the elements of an array using the default comparison defined by the IComparable<T> interface.

Syntax:

Array.Sort<T>(T[] array);

• T: Represents the type of elements in the array
• array: The one-dimensional array of type T to be sorted

Example:

using System;
class Program {
    static void Main() {
        int[] arr = { 5, 2, 8, 1 };
        Array.Sort(arr);
        foreach (int i in arr)
            Console.Write(i + " ");
    }
}

1 2 5 8 

2. Sort<T>(T[], IComparer<T>) Method

This method sorts the elements of an array using a custom comparison logic provided by the IComparer<T> interface.

Syntax:

Array.Sort<T>(T[] array, IComparer<T> comparer);

• comparer: An object that defines custom comparison logic

Example:

using System;
using System.Collections.Generic;
class DescComparer : IComparer<int> {
    public int Compare(int x, int y) {
        return y.CompareTo(x);
    }
}
class Program {
    static void Main() {
        int[] arr = { 5, 2, 8, 1 };
        Array.Sort(arr, new DescComparer());
        foreach (int i in arr)
            Console.Write(i + " ");
    }
}

8 5 2 1 

3. Sort<T>(T[], int index, int length) Method

This method sorts a specified range of elements in the array.

Syntax:

Array.Sort<T>(T[] array, int index, int length);

• index: The starting position from where sorting begins
• length: The number of elements to sort

Example:

using System;
class Program {
    static void Main() {
        int[] arr = { 9, 4, 7, 2, 8 };
        Array.Sort(arr, 1, 3);
        foreach (int i in arr)
            Console.Write(i + " ");
    }
}

9 2 4 7 8 

4. Sort<T>(T[], Comparison<T>) Method

This method sorts the array using a delegate (Comparison<T>) that defines custom comparison logic.

Syntax:

Array.Sort<T>(T[] array, Comparison<T> comparison);

• comparison: A delegate that defines custom comparison logic between elements

Example:

using System;
class Program {
    static void Main() {
        string[] arr = { "apple", "kiwi", "banana" };
        Array.Sort(arr, (a, b) => a.Length.CompareTo(b.Length));
        foreach (string s in arr)
            Console.Write(s + " ");
    }
}

kiwi apple banana 

5. Sort(Array, Array) Method

This method sorts one array (keys) and rearranges the corresponding elements in another array (values).

Syntax:

Array.Sort(Array keys, Array items);

• keys: The array containing elements to be sorted
• items: The array whose elements are rearranged according to the sorted keys

Example:

using System;
class Program {
    static void Main() {
        int[] keys = { 3, 1, 2 };
        string[] values = { "Three", "One", "Two" };
        Array.Sort(keys, values);
        for (int i = 0; i < keys.Length; i++)
            Console.WriteLine(keys[i] + " -> " + values[i]);
    }
}

1 -> One
2 -> Two
3 -> Three

These commonly used overloads of Array.Sort() are sufficient to handle most sorting scenarios efficiently in C#.