The **```Array```** class in the ```System``` namespace provides the #key# ```Reverse()``` method: used to reverse the elements of an array #key# with multiple overloads.

# Syntax
```java
public static void Reverse (Array array);
```

- This method works only for single dimensional `Arrays` and throws a ```RankException``` if the `array` passed as input is multi-dimensional. 
- It throws a ```ArgumentNullException``` if the input array is null.
- The ```Reverse()``` method does not use an auxiliary array for reversal and overwrite the existing elements of the array.
- The time complexity of ```Array.Reverse()``` method is `O(n)`, where `n` is the number of elements in the array.

In the example below, we have created and initialized an `Array` with integers. We then print the `Array` elements before calling the ```Reverse()``` method.

We then call the ```Reverse()``` method and print the `Array` contents again. 
The array elements are now reversed, so the program prints the following output.

```
Array Initial State: 11,12,13,14,15,16,17
Array After Reversal: 17,16,15,14,13,12,11
```

# Code

using System;

class HelloWorld
{
    static void Main()
    {
        int[] inputArray = new int[]{11,12,13,14,15,16,17};

        Console.WriteLine("Array Initial State: {0}",string.Join(",",inputArray));

        Array.Reverse(inputArray);
        Console.WriteLine("Array After Reversal: {0}",string.Join(",",inputArray));
    }
}

How to reverse an array in C#

Use the Array.Reverse() method to reverse single-dimensional arrays in C# with O(n) complexity.