Array Sort

Create C# console application that demonstrates array sorting using the selection sort algorithm.

Solution

The app generates an array of random integers, sorts them using a manual implementation of the selection sort algorithm, and displays both the unsorted and sorted arrays. This project is designed to help understand how sorting algorithms work at a fundamental level.

namespace ArraySort
{
    internal class Program
    {
        static void Main(string[] args)
        {
            const int count = 10;
            var m = new int[count];
            var rnd = new Random();

            // Initializing an array with random numbers
            for (int i = 0; i < count; i++)
            {
                m[i] = rnd.Next(0, 100);
            }

            // Print an array before sorting
            Console.WriteLine("m = [" + String.Join(", ", m) + "]");

            // Sorting using a simple selection sort algorithm
            // Please remember this algorithm!
            for (int i = 0; i < count; i++)
            {
                for (int j = i + 1; j < count; j++)
                {
                    if (m[i] > m[j])
                    {
                        int temp = m[i];
                        m[i] = m[j];
                        m[j] = temp;
                    }
                }
            }

            // Sorting can be done using the built-in Array class method
            // Array.Sort(m);

            // Print the array after sorting
            Console.WriteLine("m = [" + String.Join(", ", m) + "]");

        }
    }
}

Features

• Generates an array of 10 random integers (range: 0-99)
• Implements Selection Sort algorithm from scratch
• Displays the array before and after sorting
• Includes commented alternative using Array.Sort() for comparison
• Clean console output with formatted array display

Usage

Simply run the application. It will automatically:

1. Generate 10 random numbers between 0 and 99
2. Display the unsorted array
3. Sort the array using Selection Sort
4. Display the sorted array

Example Output

m = [47, 12, 89, 3, 56, 23, 91, 8, 34, 67]
m = [3, 8, 12, 23, 34, 47, 56, 67, 89, 91]

Algorithm: Selection Sort

The program uses Selection Sort, a simple comparison-based sorting algorithm that works by:

1. Starting from the first position (i = 0)
2. Comparing the current element with all elements after it (j = i+1 to end)
3. Swapping whenever a smaller element is found
4. Moving to the next position and repeating

Algorithm Characteristics

• Time Complexity: O(n²) for all cases
• Space Complexity: O(1) - sorts in-place
• Stability: Not stable in this implementation
• Best for: Small datasets, educational purposes, or when memory writes are expensive

Code Snippet

for (int i = 0; i < count; i++)
{
    for (int j = i + 1; j < count; j++)
    {
        if (m[i] > m[j])
        {
            int temp = m[i];
            m[i] = m[j];
            m[j] = temp;
        }
    }
}

Building and Running

Using Visual Studio

1. Open the project in Visual Studio
2. Press F5 or click "Start" to build and run

Using .NET CLI

dotnet run

Alternative Sorting Method

The code includes a commented-out alternative using C#'s built-in sorting:

Array.Sort(m);

This uses an optimized sorting algorithm (typically IntroSort, a hybrid of QuickSort, HeapSort, and InsertionSort) and is recommended for production code. The manual implementation is provided for educational purposes.

Educational Value

This project is excellent for:

• Learning how sorting algorithms work
• Understanding nested loops and array manipulation
• Comparing custom implementations with built-in methods
• Practicing algorithm analysis and optimization

Source Code

Please refer to the GitHub repository.