// C# program to print all
// combination of size r
// in an array of size n
using System;

public class Lab4_1Nisan2021
{
	// Driver Code
	static public void Main()
	{
		string[] choices = {"boncuk1", "boncuk2", "boncuk3", "boncuk4", "boncuk5", "boncuk6", "boncuk7"};
		int r = 2;
		int n = choices.Length;
		Console.WriteLine("You can make {0} different combinations and they're as follows: ",(n*(n-1))/r);
		printCombination(choices, n, r);
		
	}

	static void combinationUtil(string[] choices, string[] data, int start, int end, int index, int r)
	{
		// Current combination is
		// ready to be printed,
		// print it
		if (index == r)
		{
			for (int j = 0; j < r; j++)
				Console.Write(data[j] + " ");
			Console.WriteLine("");
			return;
		}

		// replace index with all
		// possible elements. The
		// condition "end-i+1 >=
		// r-index" makes sure that
		// including one element
		// at index will make a
		// combination with remaining
		// elements at remaining positions
		for (int i = start; i <= end && end - i + 1 >= r - index; i++)
		{
			data[index] = choices[i];
			combinationUtil(choices, data, i + 1, end, index + 1, r);
		}
	}

	// The main function that prints
	// all combinations of size r
	// in arr[] of size n. This
	// function mainly uses combinationUtil()
	static void printCombination(string[] choices, int n, int r)
	{
		// A temporary array to store
		// all combination one by one
		string[] data = new string[r];
		// Print all combination
		// using temprary array 'data[]'
		combinationUtil(choices, data, 0, n - 1, 0, r);
	}
}