Problem with QuickSort algorithm in C#

i wrote i quicksort algorithm in c# but it has a problem,when i compile it,it doesnt work in some conditions for example when i enter number 12,32,11 in textbox6 to sort, it gives out of range error when i go to trace it, debugger shows that num[] took nums[0]=12,nums[1]=11,nums[2]=1

Edited: i changed the while condition and it know doesnt give out of range error but when the input is 12,32,11 output 11,12,1

private void button5_Click(object sender, EventArgs e)
    {
        string[] x = textBox6.Text.Split(',');
        int[] nums = new int[x.Length];

        for (int counter = 0; counter < x.Length; counter++)
        {
开发者_开发技巧            nums[counter] = Convert.ToInt32(x[counter]);
        }

        int i = 0;
        int  j = nums.Length;
        int pivot = nums[0];
        do 
        {
            do 
            {
                    i++;
            }
                  while ((i < nums.Length) && (nums[i] < pivot));
            do
                {
                    j--;
                }
while (nums[j]>pivot);
            if (i < j)
            {
                int temp = i;

                nums[i] = nums[j];
                nums[j] = temp;

            }

        }while(i<j);
        int temp1 = nums[0];
        nums[0] = nums[j];
        nums[j] = temp1;
        int pivotpoint = j;
        string QuickSort = "";
        foreach (var n in nums)
           QuickSort += n.ToString() + ",";
        textBox5.Text = QuickSort;

    }

Your issue is that i isn't being bounds-checked in your do-while loop. i will get incremented beyond the end of your nums array. Try modifying the while condition thus:

while ((i<nums.Length) && (nums[i]<pivot))

Of course you could simply use Array.Sort(nums);