02.1.19.NumberPermutations

using System;

class NumberPermutations
{
    static void Swap(ref int first, ref int second)
    {
        int temp = first;
        first = second;
        second = temp;
    }

    static void Permutations(int[] vector, int numbersLength, int start)
    {

        if (start == numbersLength)
        {
            Print(vector);
        }
        else
        {
            for (int i = start; i <= numbersLength; i++)
            {
                Swap(ref vector[i], ref vector[start]);
                Permutations(vector, numbersLength, start + 1);
                Swap(ref vector[i], ref vector[start]);
            }
        }
    }

    static void LoadVector(int[] vector, int vectorLenght)
    {
        for (int i = 0; i < vectorLenght; i++)
        {
            vector[i] = i + 1;
        }
        Permutations(vector, vectorLenght-1, 0);
    }

    static void Print(int[] vector)
    {
        foreach (int i in vector)
        {
            Console.Write("{0} ", i);
        }
        Console.WriteLine();
    }

    static void Main()
    {
        Console.Write("Please enter the amount of the numbers 1...N, N = ");
        int numberN = int.Parse(Console.ReadLine());
        int[] vector = new int[numberN];
        LoadVector(vector, numberN);
    }
}