Question

I have a problem with creating a sliding puzzle. I’m trying to make a method to reset & shuffle all 15 buttons, but the problem is the random numbers are repeated.

When I write bool[] usednum = new bool[array.length]; I get an error, so I increase the length of the usednum array …..

private void reset()
{
    int[] array = { 1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
    int count = 0;
    Random r = new Random();
    bool[] usednum = new bool[50];

    for (int i = 0; i < usednum.Length; i++)
        usednum[i] = false;

    while (count < array.Length)
    {
        int temp = array[r.Next(array.Length)];
        if (usednum[temp] == false)
        {
            button1.Text = temp.ToString();
            usednum[temp] = true;
            count++;
        }

        temp = array[r.Next(array.Length)];
        if (usednum[temp] == false)
        {
            button2.Text = temp.ToString();
            usednum[temp] = true;
            count++;
        }

        temp = array[r.Next(array.Length)];
        if (usednum[temp] == false)
        {
            button3.Text = temp.ToString();
            usednum[temp] = true;
            count++;
        }

        temp = array[r.Next(array.Length)];
        if (usednum[temp] == false)
        {
            button4.Text = temp.ToString();
            usednum[temp] = true;
            count++;
        }

        temp = array[r.Next(array.Length)];
        if(usednum[temp] == false)
        {
            button5.Text = temp.ToString();
            usednum[temp] = true;
            count++;
        }

        temp = array[r.Next(array.Length)];
        if (usednum[temp] == false)
        {
            button6.Text = temp.ToString();
            usednum[temp] = true;
            count++;
        }
        /*.
        . 
        . 
        . to button 15*/

Answer 1

Just shuffle the array: http://en.wikipedia.org/wiki/Shuffling

A simple shuffle algorithm is (in pseudocode)

maxIndex = array.Length - 1
for index in 0 to maxIndex - 1
    swapIndex = random number between index and maxIndex
    swap (array, index, swapIndex)