using System;
using System.IO;
using System.Collections.Generic;
namespace Permutations_Words
{
class Class1
{
static void Main(string[] args)
{
permutation_words();
}
private static void permutation_words()
{
string[] stringInput = { "make", "money", "on", "the", "internet" };
ShowPermutations<string>(stringInput, stringInput.Length);
}
static void ShowPermutations<T>(IEnumerable<T> input, int count)
{
string path_write = @"c:\temp\Test.txt"; // You can change the path and file name
StreamWriter sw = File.CreateText(path_write);
int j;
foreach (IEnumerable<T> permutation in PermutationUtils.Permute<T>(input, count))
{
j = 0;
foreach (T pword in permutation)
{
if (j == 0)
sw.Write(pword);
else
sw.Write(" " + pword);
j++;
}
sw.WriteLine();
}
foreach (IEnumerable<T> permutation in PermutationUtils.Permute<T>(input, count))
{
sw.Write("\"");
j = 0;
foreach (T pword in permutation)
{
if (j == 0)
sw.Write(pword);
else
sw.Write(" " + pword);
j++;
}
sw.Write("\"");
sw.WriteLine();
}
foreach (IEnumerable<T> permutation in PermutationUtils.Permute<T>(input, count))
{
sw.Write("[");
j = 0;
foreach (T pword in permutation)
{
if (j == 0)
sw.Write(pword);
else
sw.Write(" " + pword);
j++;
}
sw.Write("]");
sw.WriteLine();
}
sw.Close();
}
}
class PermutationUtils
{
public static IEnumerable<IEnumerable<T>> Permute<T>(IEnumerable<T> list, int count)
{
if (count == 0)
{
yield return new T[0];
}
else
{
int startingElementIndex = 0;
foreach (T startingElement in list)
{
IEnumerable<T> remainingItems = AllExcept(list, startingElementIndex);
foreach (IEnumerable<T> permutationOfRemainder in Permute(remainingItems, count - 1))
{
yield return Concat<T>(new T[] { startingElement }, permutationOfRemainder);
}
startingElementIndex += 1;
}
}
}
public static IEnumerable<T> Concat<T>(IEnumerable<T> x, IEnumerable<T> y)
{
foreach (T item in x) { yield return item; }
foreach (T item in y) { yield return item; }
}
public static IEnumerable<T> AllExcept<T>(IEnumerable<T> input, int indexToSkip)
{
int index = 0;
foreach (T item in input)
{
if (index != indexToSkip) yield return item;
index += 1;
}
}
}
}
