A simple implementation of Insertion Sort in C#

program.cs

bool showDebugOutput = true;

void Main()
{
	var data = new string[] { "A", "R", "L", "S", "T", "N", "E" };

	// Tell the user what's going on
	Console.WriteLine("Unsorted Data:");
	DumpData(data);
	Console.WriteLine("Sorting Data...");
	Console.WriteLine();

	DrawSeparatorLine();

	// Sort the data
	var result = InsertSort(data, true);

	DrawSeparatorLine();

	// Dump the sorted data to the console
	Console.WriteLine("Sorted Data:");
	DumpData(result);
}

string[] InsertSort(string[] data, bool desc)
{
	// Start at index 1 (we skip the first element because that's where
	// we start the comparison)
	for (int dataIndex = 1; dataIndex < data.Length; dataIndex++)
	{
		// Get the current item from our input data
		string item = data[dataIndex];

		// Note that we don't have an exit condition on this for loop
		// because we break out of the loop manually once a swap is made.
		for (int searchPointer = dataIndex - 1; searchPointer >= 0;)
		{
			if (showDebugOutput)
				WriteCompareOutput(dataIndex, searchPointer);
			if (showDebugOutput)
				WriteDebugOutput(item, data[searchPointer]);

			// Using string.CompareTo() to determine ordering
			// See https://msdn.microsoft.com/en-us/library/35f0x18w(v=vs.110).aspx
			// CompareTo returns:
			//	   -1 if item belongs before the other item
			//		0 if item is equal to the other item
			//		1 if item belongs after the other item
			
			if (item.CompareTo(data[searchPointer]) < 0)
			{
				data[searchPointer + 1] = data[searchPointer];
				searchPointer--;
				data[searchPointer + 1] = item;
			}
			else
				break;
		}
		if (showDebugOutput)
			DumpData(data);
	}

	return data;
}


// Methods for optional debug output
void WriteCompareOutput(int dataIndex, int searchPointer)
{
	Console.Write("Comparing index {0} to index {1}:  ", dataIndex, searchPointer);
}

void WriteDebugOutput(string currentItem, string other)
{
	var comparisonResult = currentItem.CompareTo(other);
	if (comparisonResult < 0)
		Console.WriteLine("{0} is less than {1} - Swapping.", currentItem, other);
	else if (comparisonResult == 0)
		Console.WriteLine("{0} is equal to {1} - No Swap.", currentItem, other);
	else
		Console.WriteLine("{0} is greater than {1} - No Swap.", currentItem, other);
}

void DumpData(string[] input)
{
	for (int i = 0; i < input.Length; i++)
	{
		Console.WriteLine(input[i]);
	}
	Console.WriteLine();
	//Console.WriteLine(input);
}

void DrawSeparatorLine()
{
	if (showDebugOutput)
		Console.WriteLine("============================================");
}